Glock barrel accuracy tests

[GJM]

http://www.victorygunblog.com/blog/barrelrace17

KKM came out on top, and there are surprises.

[cheby]

But even with the KKM barrels Glocks still shoot left and low, right? I have read that somewhere.

[Nephrology]

http://www.victorygunblog.com/blog/barrelrace17

KKM came out on top, and there are surprises.

I think I've posted this before, but here is another, similar test on Primary and Secondary (https://primaryandsecondary.com/forum/index.php?threads/glock-precision-barrel-test-1-ransom-rest-oem-kkm-s3f-zev-wilson.1727/) with slightly different results.

I think the biggest difference between the 2 tests is that Victory's uses a 3rd gen gun, while P&S' test uses a Gen 4 pistol. Both use a variety of ammunition, with some overlap.

Honestly I think both tests show that you're really splitting hairs and that all gun/barrel/ammo combinations will vary some.

[Mr_White]

Very interesting, thanks for posting!

[blues]

But even with the KKM barrels Glocks still shoot left and low, right? I have read that somewhere.

That would be of more interest to me than the half inch difference in performance among the barrels.

[Mr_White]

But even with the KKM barrels Glocks still shoot left and low, right? I have read that somewhere.


That would be of more interest to me than the half inch difference in performance among the barrels.

Ransom Rests need trigger control practice too?

[blues]

Ransom Rests need trigger control practice too?

Inquiring minds want to know...

[cheby]

Ransom Rests need trigger control practice too?

According to this, that might be the question:
https://pistol-forum.com/showthread.php?16356-Do-Glock-pistols-shoot-left-and-if-so-why

[Nephrology]

The "low" part is unquestionably shooter error... as is the "left" shift in probably 90-95% of guns.

Of my 7 Glocks, only 1 shoots demonstrably left. The rest are more or less POA/POI with the rear centered in the dovetail.

[breakingtime91]

But even with the KKM barrels Glocks still shoot left and low, right? I have read that somewhere.

not my experience (which doesn't mean anything haha) or Kyle Defoors (he is a huge fan of wilson and kkm barrels)

[cheby]

Alright guys... I guess I just got overtrolled. Disclaimer: I was kidding. Of course Glocks do not shoot low and left; some shooters do. Duh!

[blues]

Alright guys... I guess I just got overtrolled. Disclaimer: I was kidding. Of course Glocks do not shoot low and left; some shooters do. Duh!

Just when it was gettin' good...

[hiro]

Ransom Rests need trigger control practice too?

It needs to get more finger on the trigger.

[CCT125US]

Didn't BLR do a write up about how a Ransom rest favors the 1911, over polymer guns? Due to the mechanical lock up between frame, barrel, and slide. Meaning on a poly gun, the frame may stay in place, but the slide and barrel may come to rest at a slightly different position, changing the POI? Also, didn't TLG once do testing with a laser for consistent POA?

[Gray222]

These tests never seem to mirror what I've seen.

Barsto is best with consistently loaded ammo.

S3f is best with cheap ammo.

[JCS]

S3f gets a lot of hype yet the stock barrel outperformed it for the most part. It seems the barrels are picky on ammo. I'd like to see a test with more kinds of ammo.


Sent from my iPhone using Tapatalk

[joshs]

Didn't BLR do a write up about how a Ransom rest favors the 1911, over polymer guns? Due to the mechanical lock up between frame, barrel, and slide. Meaning on a poly gun, the frame may stay in place, but the slide and barrel may come to rest at a slightly different position, changing the POI? Also, didn't TLG once do testing with a laser for consistent POA?

I've always thought the same, and that's why Todd shot the test guns with a laser from a rest to eliminate potential errors from loose slide to frame fits. However, the day-to-day consistency test in the P&S thread seems to show that ransom testing can be consistent for polymer guns.

[JHC]

Alright guys... I guess I just got overtrolled. Disclaimer: I was kidding. Of course Glocks do not shoot low and left; some shooters do. Duh!

I knew it was tongue in cheek. Very good. No emoticons. Well done.

[Irelander]

Interesting article. Can't say I'll change from a stock barrel anytime soon but and interesting read.

Can't say much for their other articles.

[JHC]

Interesting read. Iv'e been reading up on various bullseye forums lately re twist rates for 9mm. Dave Sams of bullseye gun building fame was recently telling me that the faster 1:10 through 1:16 twists of 9mm barrels is baffling to him as it way too fast for best results with the 115 class bullets and for the target shooting he made his bones in, there is not much sense in shooting a heavier bullet. He worked with KKM to develop their 1911 9mm barrel option with a 1:32 twist specifically aimed at 115 grain precision stuff.
Generally the results seem to bear that out.

[CCT125US]

I've always thought the same, and that's why Todd shot the test guns with a laser from a rest to eliminate potential errors from loose slide to frame fits. However, the day-to-day consistency test in the P&S thread seems to show that ransom testing can be consistent for polymer guns.

A shift of .004 would yield .5 change in possible group size at 25 yd (6.47 sight radius). Even the perception of .004 would be hard for some folks. At lest with the Ransom rest, that shift would potentially be consistent. I also wonder how the first hand cycled round played into this.

[ST911]

The top ~3 barrels are within the bullet diameter's difference. Where's the dividing line between noise and statistical significance?

[SLG]

I read the first paragraph and then closed the window. I've never, with hundreds and hundreds of glocks, never found one that wouldn't hit a torso at 200 yards.

[PNWTO]

So, at the risk of brevity, my takeaway is still that the juice isn't worth the squeeze for most uses, assuming an otherwise stock-ish gun... ceteris parabus. My Gen 4 19 is as accurate as I can be.

[DI1]

The Gen 4 Glocks seem not to benefit from aftermarket barrels. My Gen 3 Glocks have kkm barrels and the difference from stock is maybe an inch less at 25 yards. I have a Zev dimpled barrel but have not really compared it to the kkm, it looks really cool though.


My friend who is a competitive precision shooter built a 9mm 1911 with a KKM 1/32 twist barrel. That gun consistently shoots .5" groups at 50 yards.

[JHC]

The Gen 4 Glocks seem not to benefit from aftermarket barrels. My Gen 3 Glocks have kkm barrels and the difference from stock is maybe an inch less at 25 yards. I have a Zev dimpled barrel but have not really compared it to the kkm, it looks really cool though.

Agree re Gen 4 vs 3. Also on -1" at 25. But bigger impact at 50, much bigger as in smaller. They are enjoyable to me as I particularly enjoy that sort of shooting.

[hiro]

The top ~3 barrels are within the bullet diameter's difference. Where's the dividing line between noise and statistical significance?

Somewhere between $100 and $200 (on top of the already perfectly decent stock barrel)

[blues]

Somewhere between $100 and $200 (on top of the already perfectly decent stock barrel)

I never could quite understand replacing the OEM barrel unless it was required. I'm a slow learner obviously.

(ETA: Obviously, I'm not trying to wring every last bit out of the guns either, so my needs are quite a bit different from those who compete. My Glocks are relegated to more mundane usage and have been more than adequate for my prior years in LE as well as home and self defense.)

[JHC]

I never could quite understand replacing the OEM barrel unless it was required. I'm a slow learner obviously.

It makes little arguable sense unless you get a buzz off of fewer 1.5" guns vs more 3" guns. More or less. I do. I blame it on squirrel plinking with a K22. ;)

[hiro]

I never could quite understand replacing the OEM barrel unless it was required. I'm a slow learner obviously.

(ETA: Obviously, I'm not trying to wring every last bit out of the guns either, so my needs are quite a bit different from those who compete. My Glocks are relegated to more mundane usage and have been more than adequate for my prior years in LE as well as home and self defense.)

I can see a Pseudo Roland Special in my (fairly far) future at which point having a threaded barrel for a comp makes sense but other than that, my shooting is too poor to benefit from upgrading the barrel and the money is better spent elsewhere.

[blues]

It makes little arguable sense unless you get a buzz off of fewer 1.5" guns vs more 3" guns. More or less. I do. I blame it on squirrel plinking with a K22. ;)

I hear ya. My squirrel plinking was done with a spring loaded BB gun to convince them to terrorize someone else's bird feeders in years past. When I got tired of having bears on the deck I took the feeders down and now the squirrels are happily chewing on my furniture. :rolleyes:

[GJM]

Just got around to reading the fine print on the study, and realized they used a Gen 3 17. Apologies if someone else already said this, but I bet a Gen 4 would have resulted in the OEM barrel shooting even better groups.

[JBP55]

Just got around to reading the fine print on the study, and realized they used a Gen 3 17. Apologies if someone else already said this, but I bet a Gen 4 would have resulted in the OEM barrel shooting even better groups.

Absolutely.

[JHC]

Just got around to reading the fine print on the study, and realized they used a Gen 3 17. Apologies if someone else already said this, but I bet a Gen 4 would have resulted in the OEM barrel shooting even better groups.

That would be my certain assumption, if'n it's slide to frame was tight. That's my predictor. The KKMs improved my 3's such that I could measure and I could not measure the change in a couple Gen 4s.

[GJM]

That would be my certain assumption, if'n it's slide to frame was tight. That's my predictor. The KKMs improved my 3's such that I could measure and I could not measure the change in a couple Gen 4s.

I have multiple brand, custom Glock barrels, and run OEM in every one of my 26/19/17 gen 4 Glocks.

[SLG]

I think it may very well be my inability to shoot glocks very accurately, but my barsto and kkm barrels do not shoot any better in my gen 3 19 than the oem barrel. They also shoot no better than any of my gen 4 guns. This is just me shooting, not ransom rested or anything.

[JHC]

I think it may very well be my inability to shoot glocks very accurately, but my barsto and kkm barrels do not shoot any better in my gen 3 19 than the oem barrel. They also shoot no better than any of my gen 4 guns. This is just me shooting, not ransom rested or anything.

Or it's the exact opposite and you shoot too well to see it. As in the Gen 3's cone of wobble is 2.5" and your cone of wobble is only 2". Whereas my cone of wobble is 4" so when the KKM barrel tightens the guns cone of wobble, I see the improvement.

It stands the sometimes conventional wisdom on its head; when folks say they don't shoot well enough to utilize the aftermarket's precision.

I believe my logic here is infallible. ;)

[Kevin B.]

I think the benefits of an aftermarket barrel is dependent on the Glock it is going in. I have had very accurate Gen3 Glocks with OEM barrels and I have had Gen3 Glocks that benefited from an aftermarket barrel. Most of my Gen4 Glocks shoot very well with the OEM barrel but I have one that benefited from a KKM.

[GJM]

My wife has a KKM, fitted Briley and Wilson in three of her gen 3 Glock 34 pistols, and feel they help accuracy in those.

[JHC]

I think the benefits of an aftermarket barrel is dependent on the Glock it is going in. I have had very accurate Gen3 Glocks with OEM barrels and I have had Gen3 Glocks that benefited from an aftermarket barrel. Most of my Gen4 Glocks shoot very well with the OEM barrel but I have one that benefited from a KKM.

On my RTF2 G17, my KKM didn't improve it such that I could measure. But that guns slide is super tight on the frame. On my OD G17 (also Gen 3) the slide had a small amount of play and I generally didn't shoot it as tight as the RTF2. Dropping the KKM into it and that play disappears. And then I could consistently shoot the OD 17 on par with the RTF2 with it's OEM barrel.

[SLG]

Or it's the exact opposite and you shoot too well to see it. As in the Gen 3's cone of wobble is 2.5" and your cone of wobble is only 2". Whereas my cone of wobble is 4" so when the KKM barrel tightens the guns cone of wobble, I see the improvement.

It stands the sometimes conventional wisdom on its head; when folks say they don't shoot well enough to utilize the aftermarket's precision.

I believe my logic here is infallible. ;)

I'll go with that, though Im reasonably sure it is incorrect in relation to me. With that particular gun, I want to say that 4" was about as good as I could do with the stock barrel. With a fitted barsto, or a drop in kkm, I dont really see any difference. That gun also has an mrds, and still I see about 4". It has been a while since I tested it though. Eitherway, my gen 4 17's shoot a fair bit better for me. Stock and no dot. Same with the 19m. Maybe my gen 3 19 is just a lemon, idk.

[JHC]

I'll go with that, though Im reasonably sure it is incorrect in relation to me. With that particular gun, I want to say that 4" was about as good as I could do with the stock barrel. With a fitted barsto, or a drop in kkm, I dont really see any difference. That gun also has an mrds, and still I see about 4". It has been a while since I tested it though. Eitherway, my gen 4 17's shoot a fair bit better for me. Stock and no dot. Same with the 19m. Maybe my gen 3 19 is just a lemon, idk.

Seems though you've recently shot that 19M into around 2". A G19. That's is the basis of my observation. Some are just "within spec" but nothing special. My GSSF award G35 (random draw, no win ;) ) was wiggle loose and I tried four loads one outing, never saw better than 4" and said the hell with you and flipped it. I saw a Gen 4 G21 than exhibited that pattern too.

[Mntneer357]

I never could quite understand replacing the OEM barrel unless it was required. I'm a slow learner obviously.

(ETA: Obviously, I'm not trying to wring every last bit out of the guns either, so my needs are quite a bit different from those who compete. My Glocks are relegated to more mundane usage and have been more than adequate for my prior years in LE as well as home and self defense.)

Yes, sir. I guess I'm a slow learner too.

Someone much smarter than me once said something to the effect of "...until you can reliably outshoot the limits of your gun, don't worry about modifications, beyond a good set of sights." After reading through my thread about Slide Cuts (https://pistol-forum.com/showthread.php?24300-Glock-Slide-Cuts-Question), I'm inclined to believe 'new barrels' also fall into the category of fools and their money being parted (except of the competition crowd - which I legitimately *do* understand).

Slainte!

[YVK]

My wife has a KKM, fitted Briley and Wilson in three of her gen 3 Glock 34 pistols, and feel they help accuracy in those.

Fitted Briley in my Gen3 19 came in with five 10-round Ransom targets, average group of underwhelming 3 inches.

[GJM]

Fitted Briley in my Gen3 19 came in with five 10-round Ransom targets, average group of underwhelming 3 inches.

That level of accuracy actually sounds very good to me, and feels analogous to the member posting here, how we need to help him with his slow 1.3 draw from concealment!

[Mr_White]

Or it's the exact opposite and you shoot too well to see it. As in the Gen 3's cone of wobble is 2.5" and your cone of wobble is only 2". Whereas my cone of wobble is 4" so when the KKM barrel tightens the guns cone of wobble, I see the improvement.

It stands the sometimes conventional wisdom on its head; when folks say they don't shoot well enough to utilize the aftermarket's precision.

I believe my logic here is infallible. ;)

That's a very interesting take on it! I'm always intrigued with the idea of getting my gun to shoot more accurately, but I also always think I'm just not accurate enough to appreciate the difference and just keep going ahead with the stock barrel.

I have a Wilson G34 barrel and in the little bit I have shot it, I didn't see any improvement from the stock Gen3 barrel. Someone who knows more about it took a look at the Wilson and said it needed a little fitting to be right in my gun, and then I went on with shooting life and never did get it fitted. So I don't think I have given the Wilson barrel a fair shake, and I keep meaning to do so sometime.

The most accurate shots I have ever made in the field were with an early Gen4 G17 and 124gr standard pressure Gold Dot. I kind of wish I could go back and attempt those shots with my current Gen3 G34 and see if I could still make them. I did a lot more pure accuracy/group shooting at the time though.

[blues]

The most accurate shots I have ever made in the field were with an early Gen4 G17 and 124gr standard pressure Gold Dot. I kind of wish I could go back and attempt those shots with my current Gen3 G34 and see if I could still make them. I did a lot more pure accuracy/group shooting at the time though.

I'm happy to read this as that is the round I loaded in all of my Gen4 G17 magazines after I took it home from my blue label dealer.

[JHC]

That's a very interesting take on it! I'm always intrigued with the idea of getting my gun to shoot more accurately, but I also always think I'm just not accurate enough to appreciate the difference and just keep going ahead with the stock barrel.

I have a Wilson G34 barrel and in the little bit I have shot it, I didn't see any improvement from the stock Gen3 barrel. Someone who knows more about it took a look at the Wilson and said it needed a little fitting to be right in my gun, and then I went on with shooting life and never did get it fitted. So I don't think I have given the Wilson barrel a fair shake, and I keep meaning to do so sometime.

The most accurate shots I have ever made in the field were with an early Gen4 G17 and 124gr standard pressure Gold Dot. I kind of wish I could go back and attempt those shots with my current Gen3 G34 and see if I could still make them. I did a lot more pure accuracy/group shooting at the time though.

The inter-relation of the respective "cones of wobble" of the gun, the ammo and the shooter is really cool but I rarely muster the patience to detail it all out. Bullseye dudes have done it to death. But pretty important to understanding the delivery of precision.

[hiro]

The inter-relation of the respective "cones of wobble" of the gun, the ammo and the shooter is really cool but I rarely muster the patience to detail it all out. Bullseye dudes have done it to death. But pretty important to understanding the delivery of precision.

I don't remember the thread but someone posted the info (I think as related by LAV) in the last few months.

[Nephrology]

Not that I am much of a shooter, but each time I consider buying an aftermarket barrel I always end up concluding that I could spend that money on higher quality ammo.

[blues]

The inter-relation of the respective "cones of wobble" of the gun, the ammo and the shooter is really cool but I rarely muster the patience to detail it all out. Bullseye dudes have done it to death. But pretty important to understanding the delivery of precision.

In terms of a thing devoutly to be wished regarding centering and accuracy...gives new meaning to waiting for the COWs to come home.

[hiro]

The inter-relation of the respective "cones of wobble" of the gun, the ammo and the shooter is really cool but I rarely muster the patience to detail it all out. Bullseye dudes have done it to death. But pretty important to understanding the delivery of precision.

I have too much time on my hands (https://pistol-forum.com/showthread.php?24003-Pistol-Precision-What-is-the-minimum-acceptable-threshold&p=554914&viewfull=1#post554914)

[JCS]

Someone posted these awhile back and I saved them. I wish I could remember who to give the credit to https://uploads.tapatalk-cdn.com/20170316/f5f17678831f457a4935b944a216cd96.jpghttps://uploads.tapatalk-cdn.com/20170316/04c8693d8ef814cef381e3b3cac68dc9.jpghttps://uploads.tapatalk-cdn.com/20170316/8f4116ebb5bc8dbf3c8d5e6c4032cf3e.jpghttps://uploads.tapatalk-cdn.com/20170316/1775736c169ab182008e6296966e81f5.jpg


Sent from my iPhone using Tapatalk

[M2CattleCo]

I've been saying that for years in response to the 'I/you can't outshoot the gun, you don't need a better gun.'

A more accurate gun is always more accurate, just maybe not shot as well as it could be.

[Mr_White]

Someone posted these awhile back and I saved them. I wish I could remember who to give the credit to https://uploads.tapatalk-cdn.com/20170316/f5f17678831f457a4935b944a216cd96.jpghttps://uploads.tapatalk-cdn.com/20170316/04c8693d8ef814cef381e3b3cac68dc9.jpghttps://uploads.tapatalk-cdn.com/20170316/8f4116ebb5bc8dbf3c8d5e6c4032cf3e.jpghttps://uploads.tapatalk-cdn.com/20170316/1775736c169ab182008e6296966e81f5.jpg


Sent from my iPhone using Tapatalk

If that's right, it makes me feel a lot better about shooting something like a ~4" group at 25 yards if the gun and ammo shoot 2.5-3" by themselves.

[GRV]

Or it's the exact opposite and you shoot too well to see it. As in the Gen 3's cone of wobble is 2.5" and your cone of wobble is only 2". Whereas my cone of wobble is 4" so when the KKM barrel tightens the guns cone of wobble, I see the improvement.

It stands the sometimes conventional wisdom on its head; when folks say they don't shoot well enough to utilize the aftermarket's precision.

I believe my logic here is infallible. ;)

I've tried, but I still don't get it. Can you expand a bit on how one can be too precise to see the benefits of more precise hardware?

[JHC]

I've tried, but I still don't get it. Can you expand a bit on how one can be too precise to see the benefits of more precise hardware?

Thanks to hiro and 1776 - see post 53 above. Play around with SLG (or we could pick on GAP, the preternatural G26 shooter) scenarios vs average 4" group shooter - who would notice more improvement in an already accurate pistol, when they had an incrementally maybe more accurate barrel.

See the final image of a 6" shooter using a 1.5" gun and how much improvement he saw vs the 6" gun. But what if that was a 2" shooter instead of a 6" shooter. I'm figuring the 2" shooter applied to that last image will have a harder time seeing what his $200 bought him.

[cheby]

I think the only reason to buy an aftermarket barrel for Glocks is to be able to shoot plated bullets, hardcast bullets, and other reloads that not suitable for the OEM when shooting a lot.

[Mr_White]

I think the only reason to buy an aftermarket barrel for Glocks is to be able to shoot plated bullets, hardcast bullets, and other reloads that not suitable for the OEM when shooting a lot.

That's definitely the reason that's most compelling to me. There seems to be enough variation from one aftermarket barrel and ammo combination to another (and what about the rest of the gun?), that I think if I truly wanted to figure things out I would have to quit practicing in a way that's more meaningful to me and just shoot groups and tabulate data. And then after I got doing that with ONE gun, I'd have to repeat the whole thing with the next one and who knows if that will work out the same. Forget all that, I am busy shooting! So I'm glad there are people more interested in this than I am, so I get to know a little about it too. :)

[GRV]

Thanks to hiro and 1776 - see post 53 above. Play around with SLG (or we could pick on GAP, the preternatural G26 shooter) scenarios vs average 4" group shooter - who would notice more improvement in an already accurate pistol, when they had an incrementally maybe more accurate barrel.

See the final image of a 6" shooter using a 1.5" gun and how much improvement he saw vs the 6" gun. But what if that was a 2" shooter instead of a 6" shooter. I'm figuring the 2" shooter applied to that last image will have a harder time seeing what his $200 bought him.

For most reasonable definitions of "group size" I can think of, and with reasonable statistical assumptions, group sizes should be the square root of the sum of the squares of the relevant deviation sizes. That is, there is some intrinsic diameter of interest for the gun: d_g, and another for the shooter: d_s, and assuming the external features of the gun are always the same the group size should be sqrt(d_g^2 + d_s^2). It's possible you have to multiply by a constant at the end to account for differences between the group size definition and the intrinsic diameter definitions. There's a lot of simplification going on there, but it sounds like that's the model everyone goes with, and I think it's reasonable, but please correct me if this is off.

The first figure does not display this correctly. It's showing variances instead of standard deviations, or something. The plots do not quite agree either, even with a constant factor; though they're pretty close and I'm guessing it's because the numbers on top of the plots are based on the displayed individual samples and not truly averaged statistics. Without knowing the details I'm just guessing.


If SLG is capable of a 1" group with a hypothetical 0" gun, he should be capable of a 1.41" group with a 1" gun and a 2.24" inch group with a 2" gun. Replacing the 2" barrel in his Glock with a 1" barrel will make his group 0.83" smaller, which for him is a 37% improvement.

If I am capable of a 4" group with a hypothetical 0" gun, I should (;)) be capable of a 4.12" group with a 1" gun and a 4.47" group with a 2" gun. Replacing the 2" barrel in my Glock with a 1" barrel will only make my group 0.35" smaller which is only a 8% improvement for me.

I believe that type of analysis will always suggest that more precise shooters will see a bigger benefit (both absolute, and relative) from the better hardware. It's possible the model is wrong and it's also possible that I've made a mistake.


ETA: Actually, there is a definition of group size and statistical assumptions I can think of that should give the additive behavior shown in the first figure, as opposed to the sum of squares approach I've suggested. I don't really think it's realistic, but let's run with it for now. Assuming that behavior, all shooters will see the same absolute benefit from different hardware, but better shooters will always see a better relative benefit. Basically the same conclusion.

[JHC]

For most reasonable definitions of "group size" I can think of, and with reasonable statistical assumptions, group sizes should be the square root of the sum of the squares of the relevant deviation sizes. That is, there is some intrinsic diameter of interest for the gun: d_g, and another for the shooter: d_s, and assuming the external features of the gun are always the same the group size should be sqrt(d_g^2 + d_s^2). It's possible you have to multiply by a constant at the end to account for differences between the group size definition and the intrinsic diameter definitions. There's a lot of simplification going on there, but it sounds like that's the model everyone goes with, and I think it's reasonable, but please correct me if this is off.

The first figure does not display this correctly. It's showing variances instead of standard deviations, or something. The plots do not quite agree either, even with a constant factor; though they're pretty close and I'm guessing it's because the numbers on top of the plots are based on the displayed individual samples and not truly averaged statistics. Without knowing the details I'm just guessing.


If SLG is capable of a 1" group with a hypothetical 0" gun, he should be capable of a 1.41" group with a 1" gun and a 2.24" inch group with a 2" gun. Replacing the 2" barrel in his Glock with a 1" barrel will make his group 0.83" smaller, which for him is a 37% improvement.

If I am capable of a 4" group with a hypothetical 0" gun, I should (;)) be capable of a 4.12" group with a 1" gun and a 4.47" group with a 2" gun. Replacing the 2" barrel in my Glock with a 1" barrel will only make my group 0.35" smaller which is only a 8% improvement for me.

I believe that type of analysis will always suggest that more precise shooters will see a bigger benefit (both absolute, and relative) from the better hardware. It's possible the model is wrong and it's also possible that I've made a mistake.

WUUT???


;)



Maybe it's how the different "cones" can partially overlap but also compound each other's variance. Like a 4" shooter with a 2" gun/ammo could be 6" out. Do your formulae capture that?

You may have it right. I'm outta runway here. :eek:

[CCT125US]

For most reasonable definitions of "group size" I can think of, and with reasonable statistical assumptions, group sizes should be the square root of the sum of the squares of the relevant deviation sizes. That is, there is some intrinsic diameter of interest for the gun: d_g, and another for the shooter: d_s, and assuming the external features of the gun are always the same the group size should be sqrt(d_g^2 + d_s^2). It's possible you have to multiply by a constant at the end to account for differences between the group size definition and the intrinsic diameter definitions. There's a lot of simplification going on there, but it sounds like that's the model everyone goes with, and I think it's reasonable, but please correct me if this is off.

The first figure does not display this correctly. It's showing variances instead of standard deviations, or something. The plots do not quite agree either, even with a constant factor; though they're pretty close and I'm guessing it's because the numbers on top of the plots are based on the displayed individual samples and not truly averaged statistics. Without knowing the details I'm just guessing.


If SLG is capable of a 1" group with a hypothetical 0" gun, he should be capable of a 1.41" group with a 1" gun and a 2.24" inch group with a 2" gun. Replacing the 2" barrel in his Glock with a 1" barrel will make his group 0.83" smaller, which for him is a 37% improvement.

If I am capable of a 4" group with a hypothetical 0" gun, I should (;)) be capable of a 4.12" group with a 1" gun and a 4.47" group with a 2" gun. Replacing the 2" barrel in my Glock with a 1" barrel will only make my group 0.35" smaller which is only a 8% improvement for me.

I believe that type of analysis will always suggest that more precise shooters will see a bigger benefit (both absolute, and relative) from the better hardware. It's possible the model is wrong and it's also possible that I've made a mistake.


ETA: Actually, there is a definition of group size and statistical assumptions I can think of that should give the additive behavior shown in the first figure, as opposed to the sum of squares approach I've suggested. I don't really think it's realistic, but let's run with it for now. Assuming that behavior, all shooters will see the same absolute benefit from different hardware, but better shooters will always see a better relative benefit. Basically the same conclusion.

After I start drinking on Friday night, I am going to reread this. It should be easier to convince myself I understood that. Well done sir. Well done.

[SLG]

For most reasonable definitions of "group size" I can think of, and with reasonable statistical assumptions, group sizes should be the square root of the sum of the squares of the relevant deviation sizes. That is, there is some intrinsic diameter of interest for the gun: d_g, and another for the shooter: d_s, and assuming the external features of the gun are always the same the group size should be sqrt(d_g^2 + d_s^2). It's possible you have to multiply by a constant at the end to account for differences between the group size definition and the intrinsic diameter definitions. There's a lot of simplification going on there, but it sounds like that's the model everyone goes with, and I think it's reasonable, but please correct me if this is off.

The first figure does not display this correctly. It's showing variances instead of standard deviations, or something. The plots do not quite agree either, even with a constant factor; though they're pretty close and I'm guessing it's because the numbers on top of the plots are based on the displayed individual samples and not truly averaged statistics. Without knowing the details I'm just guessing.


If SLG is capable of a 1" group with a hypothetical 0" gun, he should be capable of a 1.41" group with a 1" gun and a 2.24" inch group with a 2" gun. Replacing the 2" barrel in his Glock with a 1" barrel will make his group 0.83" smaller, which for him is a 37% improvement.

If I am capable of a 4" group with a hypothetical 0" gun, I should (;)) be capable of a 4.12" group with a 1" gun and a 4.47" group with a 2" gun. Replacing the 2" barrel in my Glock with a 1" barrel will only make my group 0.35" smaller which is only a 8% improvement for me.

I believe that type of analysis will always suggest that more precise shooters will see a bigger benefit (both absolute, and relative) from the better hardware. It's possible the model is wrong and it's also possible that I've made a mistake.


ETA: Actually, there is a definition of group size and statistical assumptions I can think of that should give the additive behavior shown in the first figure, as opposed to the sum of squares approach I've suggested. I don't really think it's realistic, but let's run with it for now. Assuming that behavior, all shooters will see the same absolute benefit from different hardware, but better shooters will always see a better relative benefit. Basically the same conclusion.

I really don't know what is written here, but I wish I shot that well.

[octagon]

For most reasonable definitions of "group size" I can think of, and with reasonable statistical assumptions, group sizes should be the square root of the sum of the squares of the relevant deviation sizes. That is, there is some intrinsic diameter of interest for the gun: d_g, and another for the shooter: d_s, and assuming the external features of the gun are always the same the group size should be sqrt(d_g^2 + d_s^2). It's possible you have to multiply by a constant at the end to account for differences between the group size definition and the intrinsic diameter definitions. There's a lot of simplification going on there, but it sounds like that's the model everyone goes with, and I think it's reasonable, but please correct me if this is off.

The first figure does not display this correctly. It's showing variances instead of standard deviations, or something. The plots do not quite agree either, even with a constant factor; though they're pretty close and I'm guessing it's because the numbers on top of the plots are based on the displayed individual samples and not truly averaged statistics. Without knowing the details I'm just guessing.


If SLG is capable of a 1" group with a hypothetical 0" gun, he should be capable of a 1.41" group with a 1" gun and a 2.24" inch group with a 2" gun. Replacing the 2" barrel in his Glock with a 1" barrel will make his group 0.83" smaller, which for him is a 37% improvement.

If I am capable of a 4" group with a hypothetical 0" gun, I should (;)) be capable of a 4.12" group with a 1" gun and a 4.47" group with a 2" gun. Replacing the 2" barrel in my Glock with a 1" barrel will only make my group 0.35" smaller which is only a 8% improvement for me.

I believe that type of analysis will always suggest that more precise shooters will see a bigger benefit (both absolute, and relative) from the better hardware. It's possible the model is wrong and it's also possible that I've made a mistake.


ETA: Actually, there is a definition of group size and statistical assumptions I can think of that should give the additive behavior shown in the first figure, as opposed to the sum of squares approach I've suggested. I don't really think it's realistic, but let's run with it for now. Assuming that behavior, all shooters will see the same absolute benefit from different hardware, but better shooters will always see a better relative benefit. Basically the same conclusion.

I thought this board was friendly toward cops. What's with this math stuff? :-)

[GRV]

I really don't know what is written here, but I wish I shot that well.

So do I. I gave us both the complimentary PF.com online skill boost.

[Mr_White]

For most reasonable definitions of "group size" I can think of, and with reasonable statistical assumptions, group sizes should be the square root of the sum of the squares of the relevant deviation sizes. That is, there is some intrinsic diameter of interest for the gun: d_g, and another for the shooter: d_s, and assuming the external features of the gun are always the same the group size should be sqrt(d_g^2 + d_s^2). It's possible you have to multiply by a constant at the end to account for differences between the group size definition and the intrinsic diameter definitions. There's a lot of simplification going on there, but it sounds like that's the model everyone goes with, and I think it's reasonable, but please correct me if this is off.

The first figure does not display this correctly. It's showing variances instead of standard deviations, or something. The plots do not quite agree either, even with a constant factor; though they're pretty close and I'm guessing it's because the numbers on top of the plots are based on the displayed individual samples and not truly averaged statistics. Without knowing the details I'm just guessing.


If SLG is capable of a 1" group with a hypothetical 0" gun, he should be capable of a 1.41" group with a 1" gun and a 2.24" inch group with a 2" gun. Replacing the 2" barrel in his Glock with a 1" barrel will make his group 0.83" smaller, which for him is a 37% improvement.

If I am capable of a 4" group with a hypothetical 0" gun, I should (;)) be capable of a 4.12" group with a 1" gun and a 4.47" group with a 2" gun. Replacing the 2" barrel in my Glock with a 1" barrel will only make my group 0.35" smaller which is only a 8% improvement for me.

I believe that type of analysis will always suggest that more precise shooters will see a bigger benefit (both absolute, and relative) from the better hardware. It's possible the model is wrong and it's also possible that I've made a mistake.


ETA: Actually, there is a definition of group size and statistical assumptions I can think of that should give the additive behavior shown in the first figure, as opposed to the sum of squares approach I've suggested. I don't really think it's realistic, but let's run with it for now. Assuming that behavior, all shooters will see the same absolute benefit from different hardware, but better shooters will always see a better relative benefit. Basically the same conclusion.

Count me among the people who appreciate that you did this but do not understand. :)

Fortunately, I do understand a potential heuristic substitute:

Shoot gun while paying attention, lots of attention, until gun breaks, then try to break another one while paying even more attention, and continue into perpetuity.

[GRV]

What really needs to be done to be more rigorous, even assuming everything is ideal and simple, is a fair bit more complicated and I can't quite wrap my head around it for a simple calculation to post here. AFAIK, measuring groups by maximum distance between a fixed small number of shots (e.g. biggest distance between 5 shots), isn't going to be analogous to either standard deviation nor variance. It'd be easier to just do some simulations like here: http://www.the-long-family.com/group_size_analysis.htm. But what I should do is just get back to work.

[blues]

All I got was...


WHEREAS, it is to the material advantage of the party of the second part to effect this encroachment, and the party of the first part in the exercise of authority conferred upon it by statute, is willing to permit the encroachment within the limits of the right of way as indicated, subject to the conditions of this agreement;
NOW, THEREFORE, IT IS AGREED that the party of the first part hereby grants to the party of the second part the right and privilege to make this encroachment as shown on attached plan sheet(s), specifications and special provisions which are made a part hereof upon the following conditions, to wit:
That the said party of the second part binds and obligates himself to install and maintain the encroaching facility in such safe and proper condition that it will not interfere with or endanger travel upon said highway, nor obstruct nor interfere with the proper maintenance thereof, to reimburse the party of the first part for the cost incurred for any repairs or maintenance to its roadways and structures necessary due to the installation and existence of the facilities of the party of the second part, and if at any time the party of the first part shall require the removal of or changes in the location of the said facilities, that the said party of the second part binds himself, his successors and assigns, to promptly remove or alter the said facilities, in order to conform to the said requirement, without any cost to the party of the first part.


...or something like it...

[Gray222]

For most reasonable definitions of "group size" I can think of, and with reasonable statistical assumptions, group sizes should be the square root of the sum of the squares of the relevant deviation sizes. That is, there is some intrinsic diameter of interest for the gun: d_g, and another for the shooter: d_s, and assuming the external features of the gun are always the same the group size should be sqrt(d_g^2 + d_s^2). It's possible you have to multiply by a constant at the end to account for differences between the group size definition and the intrinsic diameter definitions. There's a lot of simplification going on there, but it sounds like that's the model everyone goes with, and I think it's reasonable, but please correct me if this is off.

The first figure does not display this correctly. It's showing variances instead of standard deviations, or something. The plots do not quite agree either, even with a constant factor; though they're pretty close and I'm guessing it's because the numbers on top of the plots are based on the displayed individual samples and not truly averaged statistics. Without knowing the details I'm just guessing.


If SLG is capable of a 1" group with a hypothetical 0" gun, he should be capable of a 1.41" group with a 1" gun and a 2.24" inch group with a 2" gun. Replacing the 2" barrel in his Glock with a 1" barrel will make his group 0.83" smaller, which for him is a 37% improvement.

If I am capable of a 4" group with a hypothetical 0" gun, I should (;)) be capable of a 4.12" group with a 1" gun and a 4.47" group with a 2" gun. Replacing the 2" barrel in my Glock with a 1" barrel will only make my group 0.35" smaller which is only a 8% improvement for me.

I believe that type of analysis will always suggest that more precise shooters will see a bigger benefit (both absolute, and relative) from the better hardware. It's possible the model is wrong and it's also possible that I've made a mistake.


ETA: Actually, there is a definition of group size and statistical assumptions I can think of that should give the additive behavior shown in the first figure, as opposed to the sum of squares approach I've suggested. I don't really think it's realistic, but let's run with it for now. Assuming that behavior, all shooters will see the same absolute benefit from different hardware, but better shooters will always see a better relative benefit. Basically the same conclusion.

You edited it before I got a chance to add in that statistical assumptions are basically all we can do to infer what the results would be in anyone of these "tests."

Good thought process.

[Default.mp3]

If that's right, it makes me feel a lot better about shooting something like a ~4" group at 25 yards if the gun and ammo shoot 2.5-3" by themselves.I made those pictures in another thread. Here's how I derived them.
To expand a little on my previous post, I whipped up a couple of graphics in Excel. I just used a uniformly random distribution for both shooter's muzzle alignment and the gun's intrinsic accuracy. The 95% group was calculated using the STDEV.S function in Excel, and multiplying it to get 4 σs worth of distance (which I think is the correct way to do it?).Source: https://pistol-forum.com/showthread.php?24003-Pistol-Precision-What-is-the-minimum-acceptable-threshold&p=558152&viewfull=1#post558152

[Default.mp3]

Thanks to hiro and 1776 - see post 53 above. Play around with SLG (or we could pick on GAP, the preternatural G26 shooter) scenarios vs average 4" group shooter - who would notice more improvement in an already accurate pistol, when they had an incrementally maybe more accurate barrel.

See the final image of a 6" shooter using a 1.5" gun and how much improvement he saw vs the 6" gun. But what if that was a 2" shooter instead of a 6" shooter. I'm figuring the 2" shooter applied to that last image will have a harder time seeing what his $200 bought him.Images generated the same way I did the last batch:
https://c1.staticflickr.com/3/2859/32665492973_4d838a1019_o.png
https://c2.staticflickr.com/4/3822/32636207294_b5d6720644_o.png
https://c1.staticflickr.com/1/767/33479584855_728cbf8b1b_o.png
https://c1.staticflickr.com/3/2934/33323542602_542673bb94_o.png

[TiroFijo]

No surprises here with the statistical group analysis, good job...

Regarding the test: it's a sample of one :rolleyes: , folks... excluding the "factory glock" and "glock threaded" which are basically the same OEM barrels

Thy different ammo, and other barrels of the same brands, and you'll likely see different results.

Or simply run the tests again from zero, with all components the same :D

This test, as far as I can tell, basically tells: "don't bother to change you stock barrel" (at least, if accuracy is what you are after with a drop-in barrel).

I bet a fitted, high quality barrel would give a more meaningful gain.

[Mr_White]

Thanks Default.mp3 for those additional images!

[GRV]

At a glance Default.mp3's new images seem to corroborate what I was suggesting, which is that a better shooter will always see more benefit (both absolute and relative) with better equipment than a worse shooter.

His data is looking at what percentage of shots fall in a certain size area. I think that's a pretty good model, and that's basically what I was thinking about when I posted my numbers. However, the truth is that group shooting is a different beast. For good measure I've gone ahead and done some simulations.

Like Default.mp3, I'm assuming that the shooter and the gun are each responsible for a Gaussian distribution that's roughly a certain number of inches wide and that these two distributions add (statistical independence, which seems fair for internal gun modifications).

Where these plots diverge from his however is that I've imagined that each shooter shoots 1000 5-round groups. Each group is measured in the traditional way, by measuring the furthest distance between two points. Then I plot a histogram of the group sizes and statistics for them. Keep in mind, the average size of a 5-shot group is going to be quite different than say a 2-shot group or a 10-shot group for the same shooter.

14875
14876
14877
14878
14879
14880

It's not worth paying too much attention to the exact numbers for shooter and barrel precision, they are not very meaningful on their own, and it's better to think of them as placeholders for "better shooter", "worse shooter", "better barrel", and so on.

Here are some abbreviated results comparing 2" barrel to 1" barrel average 5-shot group sizes for various shooters:
3" shooter: 3.26" vs. 2.93" = 0.33" improvement (10%)
2" shooter: 2.63" vs. 2.04" = 0.59" improvement (22%)
1" shooter: 2.04" vs. 1.31" = 0.73" improvement (36%)
0.5" shooter: 1.9" vs. 1.03" = 0.87" improvement (46%)

Again, this suggests the better shooter sees more improvement regardless of whether the shooters are better or worse than the equipment itself.

My code could be screwed up, and to be honest I defined shooter and barrel precision by a hand-calibrated confidence interval that could be totally bogus. That shouldn't really effect the conclusion. But, if people want to look for errors or experiment with different group sizes, numbers of trials, and parameters, here's the python code:



import numpy as np
import matplotlib.pyplot as plt
from scipy.spatial.distance import pdist

num_of_groups = 1000
shots_per_group = 5
shooter_precision = 0.5 # inches
barrel_precision = 0 # inches

confidence_tuning = 0.3 # 0.3 -> precision = full-width-quarter-max

def cov(precision):
return [[(confidence_tuning * precision)**2, 0], [0, (confidence_tuning * precision)**2]]

def samples(precision):
return np.random.multivariate_normal([0,0], cov(precision), shots_per_group)

def group_size(group):
return np.amax(pdist(group))

def group_sizes(shooter_prec, barrel_prec):
output = []
for i in range(num_of_groups):
group = np.add(samples(shooter_prec), samples(barrel_prec))
output.append(group_size(group))
return output


dataset = group_sizes(shooter_precision, barrel_precision)


# Plot results:

fig = plt.figure()
fig.suptitle(str(shooter_precision)+'-inch Shooter with '+str(barrel_precision)+'-inch Barrel', fontsize=14, fontweight='bold')
ax = fig.add_subplot(111)
fig.subplots_adjust(top=0.85)
ax.set_title(str(num_of_groups)+' '+str(shots_per_group)+'-shot groups\naverage group size: '+"{0:.2f}".format(np.average(dataset))+' inches, std. dev.: '+ "{0:.2f}".format(np.std(dataset))+" inches")

ax.set_xlabel('size (inches)')
ax.set_ylabel('# of groups')

ax.hist(dataset, bins=np.linspace(0,11,22))
plt.show()



If I wanted to do the actual theoretical math to verify this, which would let us remove the Gaussian assumption and get a parameter-independent result, I wouldn't be bored enough to be on PF.

But I agree with voodoo_man, it's all bullshit unless it adds up in meatspace. So, if SLG is willing to provide all the ammo, equipment, location, and and his time, I will gladly shoot 1000 5-round groups with him........for science! ;)


ETA: The confidence interval was total BS. I retweaked it so that shooter and barrel precisions now correspond to full-width-quarter-maximum, which seems to correspond nicely to average 5-round group capabilities.

[SLG]

My very informal experience tells me that the latest graphs from member default.2.math closely correlate to my guns and shooting. My spec'd 1911 will hold 1.5" groups, and I can shoot at or slightly above 2" with them almost all the time. 5 shots, not 10,000. My 2.25" guns, like my 19M or gen4 17 (close enough, I think) hold to 3" or so for me. Sometimes less, sometimes more. My gen 3 19 is likely a 4" gun, and I am lucky to see 4" with it. I've never owned a 6" gun, unless you count my GAP rifle, but that's 6" at 1000. :-)

Anyway, the above is just swagging it, but it seems plausible, at least to me. If I drank much, it would likely seem more plausible, so if any of you disagree, try drinking heavily first. :-)

[JHC]

Regarding Default's post #71 and the graphic showing what a 2" shooter sees going from say his OEM 2.25" barrel to his aftermarket 1.5" barrel suggests to me that it might well be difficult for him to appreciate re his $200 purchase. If that's a 20% improvement I'm not sure how well two B8s communicate that since most would only see 5 or max 10 bullet holes on target vs 1000 shots forming that group.

In the past, the graphics I've seen displaying the overlay of the cones (cones because the point of each cone is the gun's muzzle right? And the open end of the cone is dispersion on target) include a result where the farthest to the right limit impact of the gun, (for a 4" gun that is four inches to the right of the POA), is ADDED to the shooter's skill cone of, maybe 3" because he was wobbled out that far when he fired, so that there is a 7 inch to the right impact.

For the 6" guns wielded by the 2" shooter, there should be some impacts outside the 8" diameter reference. Shots he broke the shot at his farthermost one direction 2", while the gun threw the shot 6" that same direction (an 8" radius).

This is the "compounded" effect I asked about a couple pages back. I'm not seeing those impacts reflected here am I? Is this old school "cone" model wrong?

[Default.mp3]

In the past, the graphics I've seen displaying the overlay of the cones (cones because the point of each cone is the gun's muzzle right? And the open end of the cone is dispersion on target) include a result where the farthest to the right limit impact of the gun, (for a 4" gun that is four inches to the right of the POA), is ADDED to the shooter's skill cone of, maybe 3" because he was wobbled out that far when he fired, so that there is a 7 inch to the right impact.

For the 6" guns wielded by the 2" shooter, there should be some impacts outside the 8" diameter reference. Shots he broke the shot at his farthermost one direction 2", while the gun threw the shot 6" that same direction (an 8" radius).

This is the "compounded" effect I asked about a couple pages back. I'm not seeing those impacts reflected here am I? Is this old school "cone" model wrong?For a 6" gun/ammo combo shot by a 2" shooter, there should not be any impacts outside the 8", but there could in theory be a shot that lands right on the 8" circle. Here is a 10k shot version:
https://c1.staticflickr.com/3/2826/33336347072_b6e7e663dc_o.png
As you can see, there are several shots that land almost right on the edge of the circle. However, to actually do so is extremely rare, simply because it's two different distributions being additively combined. There is bias toward the middle since with a uniformly random distribution, you'll have an equal opportunity for for the shooter to pull to the left or right; same deal with the gun. However, in order to get to the edges, you need both the shooter and the gun to pull in the same direction; then, you also need both components to be maxed out. This is an unlikely scenario.

Think of it as rolling two 6-sided dice: you can, in theory, get up to 12, but you're much more likely to get something in the middle. Now, ratchet it up to 100 dice; you're very unlikely to get 600 or 100, but many of your throws will be toward 300, despite the fact that each individual die has an equal opportunity to get any number, including 1 or 6.

[JHC]

Thanks that helps a lot. I don't know how unlikely it is for the shooter's max error to be additive to the guns max error. I see flyers regularly that could be explained by that. :D

[GRV]

If there is a "max error", then yes, they should add. However, Default.mp3 gave a great explanation in terms of dice why this doesn't really correspond to what you'd see on paper in terms of average group size. Assuming simple statistical models are accurate, what you really see is closer to the Pythagorean formula, not just adding.

Whether or not there is a max error is a separate issue. The model Default.mp3 and I have assumed doesn't have a max error. In theory, you can throw a shot by any amount, but it gets really unlikely the further out you go.

It's hard to explain all the details online, but it might make for an interesting sidebar conversation next week :cool:

At this point, I'm pretty thoroughly convinced that the better shooter always benefits more, period. But, I could still be wrong.

What the shooter "sees" is a different question entirely, and that's interesting. To me, comparing the 6" 3" and 1.5" targets that Default.mp3 generated for the good and bad shooters, it looks like a more dramatic improvement for the better shooter.

[BN]

On the strength of this thread, I bought a Blacklist barrel to play with in my many Glock 17's. I mostly shoot Bayou coated 147 grain bullets, so the 1 in 10 twist was interesting. So far, my limited testing seems to show that the Blacklist is more accurate.

It's interesting that the G-17 I have shot the most consistently tight groups with is an old Gen 2 with a replacement slide and the original barrel. The slide probably has less than 5000 rounds through it. The barrel has many, many more. That was my wife's main competition gun for many years until the slide cracked and Glock replaced it. She started shooting a different Glock at that time.

The Blacklist barrel has no play when it is dropped into the slide. All the Glock barrels have play. I probably have 2 or 3 hundred rounds through the Blacklist barrel at this time.

All groups have been fired hand held at 20 yards.

[RevolverRob]

Dragging this thread up from the depths, to contribute the following two tests by Fire-4-effect and covered by Recoil -

http://www.recoilweb.com/aftermarket-glock-barrel-testing-127282.html

http://www.recoilweb.com/fire-4-effect-glock-barrel-testing-part-2-unexpected-results-127423.html

My take away here is that ammunition choice makes a big difference with Glock aftermarket barrels, more so than might be expected compared to other platforms (e.g., 1911).

[JSGlock34]

I'm curious to see additional testing of the Glock GEN5/M "Marksman" barrels, but with sub-2" groups with Speer G2, I'm very impressed with the accuracy from an OEM barrel.

[RevolverRob]

I'm curious to see additional testing of the Glock GEN5/M "Marksman" barrels, but with sub-2" groups with Speer G2, I'm very impressed with the accuracy from an OEM barrel.

Me too!

I'm excited by the prospect that the factory Gen 5 barrels are more capable than previous generations. I'm also really quite impressed with the SilencerCo threaded barrel tests (in the article I linked), which produced a 0.68" group in fixed testing and then again when shooting 147-grain bullets (which you'd think, since SilencerCo is building barrels for suppression, that 147s would be optimized for it).

[Gio]

Dragging this thread up from the depths, to contribute the following two tests by Fire-4-effect and covered by Recoil -

http://www.recoilweb.com/aftermarket-glock-barrel-testing-127282.html

http://www.recoilweb.com/fire-4-effect-glock-barrel-testing-part-2-unexpected-results-127423.html

My take away here is that ammunition choice makes a big difference with Glock aftermarket barrels, more so than might be expected compared to other platforms (e.g., 1911).

Interesting tests, however, I'm a little skeptical on the 147gr tests out of the ransom rest that showed some ransom rest groups were smaller than the fixed barrel tests. I don't see how that is physically possible.

Ammunition makes a huge difference in any barrel/gun testing. I've experienced 2" groups vs 5" groups with the same brass, bullets, primers, and powder charge, but a +/- .02" difference in oal. I've seen the same kind of variation in accuracy by using different powders to make the exact same velocity/powerfactor with the same projectile.

[RevolverRob]

Interesting tests, however, I'm a little skeptical on the 147gr tests out of the ransom rest that showed some ransom rest groups were smaller than the fixed barrel tests. I don't see how that is physically possible.

Ammunition makes a huge difference in any barrel/gun testing. I've experienced 2" groups vs 5" groups with the same brass, bullets, primers, and powder charge, but a +/- .02" difference in oal. I've seen the same kind of variation in accuracy by using different powders to make the exact same velocity/powerfactor with the same projectile.

Actually, I can see how this occurred. If you check their fixed barrel tests, they provide a "variability" metric. I'm not entirely sure how it was calculated (since I can't download the White Paper), but my guess is this is a ranged variability metric from the average (e.g., standard variance from the mean of a standard distribution). In all cases, there is a considerable amount of variability (ideally this value should be 0). This suggests that though they got average group sizes that are small, the range of variance between those groupings could be quite large (e.g., the 3rd shot of a grouping could consistently be farther away than the 2nd or 4th). Again, I'm spitballing, because the White Paper from these tests isn't available (which by the by, makes Fire-4-Effects science invalid, in this scientist's opinion. If I can't see and investigate your results, they don't exist...).

In addition to that if you investigate the extreme spread metrics provided, you'll see that in the case of the Federal ammo vs. everything else - extreme spread is generally lower than all other ammo types (there are 4 instances where it is not out of a total of 14 tests). This tells me a couple of things 1) Federal ammo is more consistent than the Atlanta Arms and UMC ammunition types, and two that there may be something inherent in 147-grain ammunition that reduces extreme spread.

Given high variance and more consistent ammunition, it doesn't surprise me if ransom rests produce more accurate groups. Even the industry engineers Recoil interviewed for this piece, suggested as much. That this isolates away external geometry and gives a since of "intrinsic" accuracy, but isn't how they would test accuracy of a given handgun barrel.

[TiroFijo]

If you repeat ANY of these tests (same gun, barrel, ammo, fixture, etc.) the results most probably will be different, and in some cases with a significant variation...

[SC_Dave]

Two questions I have after reading this:

Realizing that I am NOT a great shooter, heck I may not even say I'm an average shooter, but, I work tirelessly on grip and trigger control for accuracy. I have had a aftermarket barrel in my "cart" to purchase more times than I can remember only to never be able to hit the order button because I don't know if it would truly help me or it would be money better spent on ammunition. I have waffled on this for years now. After reading this entire thread I still don't have a clear answer. This may be the question we are all asking ourselves........ Is it worth it?

Side question:
In this thread their was mention of shooting "better" ammunition for accuracy. Short of self defense ammo is there a high quality practice/target ammo out there?
David

[Gio]

Two questions I have after reading this:

Realizing that I am NOT a great shooter, heck I may not even say I'm an average shooter, but, I work tirelessly on grip and trigger control for accuracy. I have had a aftermarket barrel in my "cart" to purchase more times than I can remember only to never be able to hit the order button because I don't know if it would truly help me or it would be money better spent on ammunition. I have waffled on this for years now. After reading this entire thread I still don't have a clear answer. This may be the question we are all asking ourselves........ Is it worth it?

Side question:
In this thread their was mention of shooting "better" ammunition for accuracy. Short of self defense ammo is there a high quality practice/target ammo out there?
David

Matching your ammunition to your barrel is crucial for improving mechanical accuracy. Going to an aftermarket barrel won't automatically improve your pistol's mechanical accuracy, and may even make it worse if the load you were shooting was well matched to your factory barrel. That said, I have seen better average groups out of a KKM barrel than out of a stock Glock barrel, but getting to those better groups involved playing around with the specs of my ammo and doing a lot of ransom rest testing to get it dialed in. Even after all that, my competition load shoots about 1.8-2.0" out of my stock G34 barrel.

[Gio]

SC_Dave,

To answer your second question, I think practice ammo comes down to how it interacts with your gun/barrel. I want something that is accurate, cheap, and soft shooting. For factory ammo, in my experience you can rarely get all three. Atlanta Arms makes ammo that is generally accurate and soft shooting, but not too cheap. Speer Lawman 115gr FMJ is also accurate and cheap, but not soft shooting. Winchester White box is cheap and soft shooting, but not very accurate in my experience. I'm sure you get the point.

If you reload though, you can get all three, but it may take you some time and several range trips to dial in your load to your gun.

[Kirk]

From the Gen 5 thread (figured I'd ask here too).

Had a weird question. I have a RTF2 Vickers G19, and have considered adding an aftermarket barrel to it. Instead though, based on what I've read regarding the new Gen 5 barrels, they can achieve 1.5" at 25 yards with solid ammo. Does anyone know if I'd get the same type of accuracy benefits with a Gen 5 barrel in my RTF2? Wasn't sure if the barrel was improved due to specific fitting on the Gen 5, or if it is simply a better barrel. The Zev barrel I have on another G19 with RMR is a tack driver at 25 yards with 124gr, but would love to test out a Gen 5 barrel as well.

[JV_]

If I wanted a new barrel for my Glock, I wouldn't purchase an OEM barrel. There are too many good aftermarket ones, like Barsto.

[echo5charlie]

From the Gen 5 thread (figured I'd ask here too).

Had a weird question. I have a RTF2 Vickers G19, and have considered adding an aftermarket barrel to it. Instead though, based on what I've read regarding the new Gen 5 barrels, they can achieve 1.5" at 25 yards with solid ammo. Does anyone know if I'd get the same type of accuracy benefits with a Gen 5 barrel in my RTF2? Wasn't sure if the barrel was improved due to specific fitting on the Gen 5, or if it is simply a better barrel. The Zev barrel I have on another G19 with RMR is a tack driver at 25 yards with 124gr, but would love to test out a Gen 5 barrel as well.

The Gen5 barrel hood isn't compatible with your slide.

[TiroFijo]

If I wanted a new barrel for my Glock, I wouldn't purchase an OEM barrel. There are too many good aftermarket ones, like Barsto.

...and I would get a fitted barrel, just to make sure it is worth the effort.

[45dotACP]

From the Gen 5 thread (figured I'd ask here too).

Had a weird question. I have a RTF2 Vickers G19, and have considered adding an aftermarket barrel to it. Instead though, based on what I've read regarding the new Gen 5 barrels, they can achieve 1.5" at 25 yards with solid ammo. Does anyone know if I'd get the same type of accuracy benefits with a Gen 5 barrel in my RTF2? Wasn't sure if the barrel was improved due to specific fitting on the Gen 5, or if it is simply a better barrel. The Zev barrel I have on another G19 with RMR is a tack driver at 25 yards with 124gr, but would love to test out a Gen 5 barrel as well.From what I've heard, a fitted Bar-sto is probably going to get you the best accuracy.

That said, the advice above about using ammo your gun likes is pretty huge. I got a Wilson drop in for my 3rd gen G34 and while it shoots 115 grain ammo very well, it actually shot 124 grain ammo significantly worse than the OEM barrel.

My Gen 4 G17 MOS would see basically no benefit from an aftermarket barrel unless it was fitted, but shows a definite preference to 124 grain ammo.

Sent from my XT1585 using Tapatalk