Gen 4/5 G34 observations, plus more auto-forwarding fun

[Robinson]

I have acquired a Gen 4 and a Gen 5 Glock 34 (both MOS) and plan to use them in a pistol class next month. I shot them both for the first time today and just wanted to share some basic observations. Some folks on the forum have expressed that they would probably buy a Gen 5 G34 if they offered a non-MOS version so I figure there might be some interest.

Aside from the obvious differences between Gen 4 and 5 like the opening on top of the slide, the finger grooves, and mag well, the pistols aren't much different. I prefer no finger grooves so that's a plus for the Gen 5. The mag well seems to work well, although I'm not sure it's a necessity.

I do think the Gen 5 shoots just a little bit softer and flatter than the Gen 4 -- enough to be noticeable. Whether the Gen 5 is really superior is subjective I think.

As far as the MOS bit I guess it's nice to have the option to mount an optical sight at some point, though I have no plans to do so. The rear sight extends just a bit over the rear of the slide but they are okay for factory sights. I may look at alternatives down the road, as I know there are some available that don't overhang the slide.

Now for the "fun". I recently did a trial run of a CZ 75B Omega and it had problems with the slide auto-forwarding. Worse, it failed to load the first round into the chamber when it auto-forwarded when using 147gr ammo. So instead of investing the time and effort to get it squared away I punted and picked up the G34s with high confidence they would work.

Shooting at the range today, the slide on the Gen 5 always auto-forwarded when doing a slide-lock reload -- with both 115gr and 147gr ammo. It never failed to load a round into the chamber though, so it's not as bad as it could be. The Gen 4 did not do this at all. Other than that, there were no malfunctions and both guns shot great.

So... does anyone else have experience with Glocks auto-forwarding? I realize that behavior isn't the end of the world, but I don't consider it a "feature" either. Any advice is welcome.

[Magsz]

I have acquired a Gen 4 and a Gen 5 Glock 34 (both MOS) and plan to use them in a pistol class next month. I shot them both for the first time today and just wanted to share some basic observations. Some folks on the forum have expressed that they would probably buy a Gen 5 G34 if they offered a non-MOS version so I figure there might be some interest.

Aside from the obvious differences between Gen 4 and 5 like the opening on top of the slide, the finger grooves, and mag well, the pistols aren't much different. I prefer no finger grooves so that's a plus for the Gen 5. The mag well seems to work well, although I'm not sure it's a necessity.

I do think the Gen 5 shoots just a little bit softer and flatter than the Gen 4 -- enough to be noticeable. Whether the Gen 5 is really superior is subjective I think.

As far as the MOS bit I guess it's nice to have the option to mount an optical sight at some point, though I have no plans to do so. The rear sight extends just a bit over the rear of the slide but they are okay for factory sights. I may look at alternatives down the road, as I know there are some available that don't overhang the slide.

Now for the "fun". I recently did a trial run of a CZ 75B Omega and it had problems with the slide auto-forwarding. Worse, it failed to load the first round into the chamber when it auto-forwarded when using 147gr ammo. So instead of investing the time and effort to get it squared away I punted and picked up the G34s with high confidence they would work.

Shooting at the range today, the slide on the Gen 5 always auto-forwarded when doing a slide-lock reload -- with both 115gr and 147gr ammo. It never failed to load a round into the chamber though, so it's not as bad as it could be. The Gen 4 did not do this at all. Other than that, there were no malfunctions and both guns shot great.

So... does anyone else have experience with Glocks auto-forwarding? I realize that behavior isn't the end of the world, but I don't consider it a "feature" either. Any advice is welcome.

With older generations, prior to gen 5 I could reliably make Glocks auto forward on every single reload. With my 19X I find that i have yet to have the gun auto forward. How hard are you slamming the magazine into the gun and are you hitting the rear of the grip frame area where the grip plug would go?

[Robinson]

With older generations, prior to gen 5 I could reliably make Glocks auto forward on every single reload. With my 19X I find that i have yet to have the gun auto forward. How hard are you slamming the magazine into the gun and are you hitting the rear of the grip frame area where the grip plug would go?

I insert the mag hard enough to make sure it seats properly -- like what would typically be done when running the pistol. I don't use excessive force, and it doesn't take a lot of force to make it happen. My hand is pretty much centered on the bottom of the grip frame I guess. If you picture the normal reload technique with index finger extended along the front of the magazine -- that's what I do.

I did a bunch of reloads with the Gen 4 today too and it never happened once with that gun.

[TCFD273]

I insert the mag hard enough to make sure it seats properly -- like what would typically be done when running the pistol. I don't use excessive force, and it doesn't take a lot of force to make it happen. My hand is pretty much centered on the bottom of the grip frame I guess. If you picture the normal reload technique with index finger extended along the front of the magazine -- that's what I do.

I did a bunch of reloads with the Gen 4 today too and it never happened once with that gun.

I have Gen 5 and 4 34’s. I’ve never had them autoforward.....without slamming the magazine in. And I couldn’t do it consistently.

Now my reloading technique places my right thumb over the slide stop, and when I seat the mag I drop the slide.


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[navyman8903]

Thanks for the comparison. I have a gen 4 34 which I love, but I had the opportunity to hold and mess with a Gen 5 34. I really liked it. I'm holding my breath for a non-MOS version. I don't do optics at all. I think a stock 34.5 with Trij HD's would be the perfect duty/fighting gun on a belt rig. I also love how midnight black the Gen 5's are. I'm getting a 17 and 19 gen 5, I really hope they make the 34 in a non MOS version.

[Gio]

My gen5 34 autoforwarded easily for awhile. It seems to have gone away after the gun had a couple thousand rounds and dry fire trough it. I can get it to autoforward now if I am overly forceful, but my normal reloads won’t cause it.

I have a theory about the lower felt recoil. I have noticed my gen5 barrel is significantly slower than my gen4 with the same ammo. My 133 pf reloads in my gen4 are 126 pf in my gen5. This would have a noticeable impact on felt recoil. I only have a sample size of 1 though. My 19M’s chrono the same as my gen4 19’s and the recoil also feels the same.

[navyman8903]

My gen5 34 autoforwarded easily for awhile. It seems to have gone away after the gun had a couple thousand rounds and dry fire trough it. I can get it to autoforward now if I am overly forceful, but my normal reloads won’t cause it.

I have a theory about the lower felt recoil. I have noticed my gen5 barrel is significantly slower than my gen4 with the same ammo. My 133 pf reloads in my gen4 are 126 pf in my gen5. This would have a noticeable impact on felt recoil. I only have a sample size of 1 though. My 19M’s chrono the same as my gen4 19’s and the recoil also feels the same.

So they changed the lock time by changing the locking block on the barrel you think or somewhere else?

[pastaslinger]

So they changed the lock time by changing the locking block on the barrel you think or somewhere else?

Polygonal rifling tends to give better velocity
There is also variation between the same model gun just based on tolerances

Surprised by the autoforwarding thing mentioned in the OP, never experienced that with Gen 3 or 4

[Robinson]

Thanks everyone for your posts -- I honestly didn't realize that the Gen 5 uses different rifling -- the Marksman Barrel -- to attain greater accuracy. That could help explain the difference in how the guns shoot, or it could be just my two examples being different.

As for the auto-forwarding, I will probably give Glock a call and see what they say. It's not too far for me to drive to Smyrna -- maybe they can do something about it. I'm not sure I'll make it over there before my class next month, so the Gen 4 will probably be the one I use at the class with the Gen 5 as backup. Then the Gen 4 will become the training/practice gun and the Gen 5 possibly a carry gun.

If I do go to Smyrna I may also look into tritium sights at that point. For now I'm getting along fine with the factory sights.

[LittleLebowski]

I’ve never had them autoforward.....without slamming the magazine in. And I couldn’t do it consistently.

Now my reloading technique places my right thumb over the slide stop, and when I seat the mag I drop the slide.




This.

[JTQ]

My gen5 34 autoforwarded easily for awhile.
Do any of your other Glock's autoforward?

[Robinson]

TCFD273 LittleLebowski -- are you guys saying that you position your shooting hand thumb above the slide release so that you can always hit the release and not have to do anything differently based on whether the slide auto-forwards or not?

That makes perfect sense. For me, I have to shift my grip just slightly to release the slide (short thumbs and broken large thumb knuckle). During my time with the Glocks so far I've been alternating between hitting the slide release with my right thumb and my left trying to decide which is going to work better for me. I guess either way an auto-forward shouldn't cause a big problem if your actions are automatic, as long as the gun always loads a round into the chamber. But I'd still rather that the gun not auto-forward.

[TCFD273]

TCFD273 LittleLebowski -- are you guys saying that you position your shooting hand thumb above the slide release so that you can always hit the release and not have to do anything differently based on whether the slide auto-forwards or not?

That makes perfect sense. For me, I have to shift my grip just slightly to release the slide (short thumbs and broken large thumb knuckle). During my time with the Glocks so far I've been alternating between hitting the slide release with my right thumb and my left trying to decide which is going to work better for me. I guess either way an auto-forward shouldn't cause a big problem if your actions are automatic, as long as the gun always loads a round into the chamber. But I'd still rather that the gun not auto-forward.

Yep

Go to 3min mark


https://youtu.be/HMcc9OmjmWQ


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[Robinson]

TCFD273 Excellent video, thanks for the link.

[Robinson]

Preloading the slide release was something that Todd was advocate of and taught in his classes. There are a bunch of threads around here where he talked about it. Here are a couple:

Thanks Tom!

[Magsz]

The recoil stroke is longer on the gen 5. That is why it feels like it shoots softer.

[GJM]

The recoil stroke is longer on the gen 5. That is why it feels like it shoots softer.


Please elaborate.

[Magsz]

Please elaborate.

The RSA is longer on the gen 5's. I'm a physics retard so im not going to go outside of my lane and start mentioning momentum, axis, flex points, quantum time inertia bends etc but there has been much discussion regarding "stroking" of 2011's which is a very similar concept over on the Brian Enos forums.

Someone that is smarter than I am can explain why the Gen 5 feels softer because of this.

[1Rangemaster]

Just looked at my 19X(Gen5) recoil spring and a Gen4 recoil spring assembly, and the id numbers on back plate are different; that leads me to believe there is a different spring/assembly. It follows that that would make a difference in felt recoil.
To the OP, I have not had any Gen5s (17, 19, 19x and 34MOS) auto forward to date, and I just shot the state POST handgun quail which has two slide back loads(this w/19X). FWIW, I use my left(support) thumb to release slide after mag insert as I move hands back to grip. I get the thumb on top of slide release can be faster, but I mistimed it a couple of times and ended up chamber empty. I have deep respect for the late Todd Green-it’s a conscious “compromise” on my part(hell, I used to overhand).
If the original poster is close to GLOCK US headquarters, I understand they usually give good Warranty service...

[Robinson]

1Rangemaster thanks for the info.

[Robinson]

The RSA is longer on the gen 5's. I'm a physics retard so im not going to go outside of my lane and start mentioning momentum, axis, flex points, quantum time inertia bends etc but there has been much discussion regarding "stroking" of 2011's which is a very similar concept over on the Brian Enos forums.

Someone that is smarter than I am can explain why the Gen 5 feels softer because of this.

The RSA is indeed longer on the Gen 5. Another difference I hadn't noticed until now.

[secondstoryguy]

I’ve been running a set of Gen 5 34s(and a Gen 5 19) with no autoforward issues.

[Robinson]

I’ve been running a set of Gen 5 34s(and a Gen 5 19) with no autoforward issues.

It's sounding more like a trip to Smyrna is in my future.

[1Rangemaster]

If the situation bugs you, and you can address it with a visit to the actual mfg., do so.
I understand they will sell and install sights, but you should confirm by calling first.
Best of luck with your issue.

[pastaslinger]

The RSA is longer on the gen 5's. I'm a physics retard so im not going to go outside of my lane and start mentioning momentum, axis, flex points, quantum time inertia bends etc but there has been much discussion regarding "stroking" of 2011's which is a very similar concept over on the Brian Enos forums.

Someone that is smarter than I am can explain why the Gen 5 feels softer because of this.

I don't know why it's supposed to be smoother and I don't know if the Gen 5 has a different spring weight but the force is just the spring constant multiplied by the spring displacement with classical physics. Maybe they went with more travel and slightly lower spring weight

[STI]

My G17G5 auto forwarded all day today at Tac Con with American Eagle 147 and HST 147 with both full or partial mags being inserted moderately aggressively but not abusive. All factory G17G5 magazines.

[Robinson]

My G17G5 auto forwarded all day today at Tac Con with American Eagle 147 and HST 147 with both full or partial mags being inserted moderately aggressively but not abusive. All factory G17G5 magazines.

Damn. Is that something you plan to live with, or will you try to diagnose/correct the problem?

[Gio]

Do any of your other Glock's autoforward?
No.

[STI]

Damn. Is that something you plan to live with, or will you try to diagnose/correct the problem?

Hadn't considered there was a way to do that? Enlighten me ...

[Robinson]

Hadn't considered there was a way to do that? Enlighten me ...

I don't know the answer, I was asking because if you plan to try to rectify the problem I will follow with interest.

Anyway, I plan to call Smyrna next week and ask them about the auto-forwarding. See what advice they have.

[STI]

Anyway, I plan to call Smyrna next week and ask them about the auto-forwarding. See what advice they have.

That was the best idea I had too.

[Robinson]

Shooting today, the Gen 5 G34 was auto-forwarding the slide when using 147gr bullets but it didn't happen with 115gr range ammo. I'm thinking this may have something to do with the length and/or profile of the bullet.

I will still likely take the gun to Smyrna, but for now I am training myself to always hit the slide release no matter what during a reload.

[Irelander]

Is the root cause of auto-forwarding a fitment issue with the slide release tab?

[Robinson]

Is the root cause of auto-forwarding a fitment issue with the slide release tab?

I don't know, but when I discussed it with a technician at Smyrna today he suggested their first course of action would be to replace the slide stop/release.

[Magsz]

I don't know, but when I discussed it with a technician at Smyrna today he suggested their first course of action would be to replace the slide stop/release.

That's a pretty canned answer.

Basically auto forwarding happens when you slap the mag into the frame and the slide lock/release bounces in its recess ultimately coming out of the notch.

Could you get some video for us of your reload technique?

I hope you understand this is not a condemnation or your skills or anything of the sort, I would just like to look at ALL factors.

1. Reload technique.
2. The very buttery and slick gen 5 finish causing the slide release to well, slide out of that recess upon mag insertion.
3. A weak slide lock/release spring
4. Improperly machined slide stop notch (doubt it)

Granted, its a different gun with a different finish but i have to SMASH my 19X to get it to auto forward.

[STI]

I don't know, but when I discussed it with a technician at Smyrna today he suggested their first course of action would be to replace the slide stop/release.

The whole thing, or the spring? I think I have a spring.

[Robinson]

The whole thing, or the spring? I think I have a spring.

The lever.

[Robinson]

That's a pretty canned answer.

Basically auto forwarding happens when you slap the mag into the frame and the slide lock/release bounces in its recess ultimately coming out of the notch.

Could you get some video for us of your reload technique?

I hope you understand this is not a condemnation or your skills or anything of the sort, I would just like to look at ALL factors.

1. Reload technique.
2. The very buttery and slick gen 5 finish causing the slide release to well, slide out of that recess upon mag insertion.
3. A weak slide lock/release spring
4. Improperly machined slide stop notch (doubt it)

Granted, its a different gun with a different finish but i have to SMASH my 19X to get it to auto forward.

Yeah, same with my Gen 4 G34 -- it doesn't auto forward at all.

When reloading I use enough force to ensure the magazine seats properly -- I don't slam it in but I don't baby it either.

[Robinson]

Did some more experimentation with the Gen 5. I found out that where pressure is applied to the bottom of the magazine baseplate during reloading does make a difference. I've never purposely tried to put pressure on either the front or rear -- pretty much just center the bottom of the mag in my left hand during insertion. But while experimenting and seeing the auto-forward happen with dummy rounds I realized I was putting more pressure on the rear (heel) of the mag. When I changed my technique just a bit to put the pressure toward the front of the mag it didn't auto-forward. I guess I hadn't given it much thought previously because the Gen 4 doesn't auto-forward at all. This should be pretty easy to fix with a slight change to reloading technique -- at least until I can have the gun looked at (if I ever do).

[Trukinjp13]

Did some more experimentation with the Gen 5. I found out that where pressure is applied to the bottom of the magazine baseplate during reloading does make a difference. I've never purposely tried to put pressure on either the front or rear -- pretty much just center the bottom of the mag in my left hand during insertion. But while experimenting and seeing the auto-forward happen with dummy rounds I realized I was putting more pressure on the rear (heel) of the mag. When I changed my technique just a bit to put the pressure toward the front of the mag it didn't auto-forward. I guess I hadn't given it much thought previously because the Gen 4 doesn't auto-forward at all. This should be pretty easy to fix with a slight change to reloading technique -- at least until I can have the gun looked at (if I ever do).

Could it have something to do with the flared magwell? Maybe the mag is going in just enough deeper than on the gen 4.

I have seen a g17 with some big ol aftermarket magwell cause problems because of this. Mag was going in too deep when doing mag changes at speed.

[Trukinjp13]

Double post

[Robinson]

Could it have something to do with the flared magwell? Maybe the mag is going in just enough deeper than on the gen 4.

I have seen a g17 with some big ol aftermarket magwell cause problems because of this. Mag was going in too deep when doing mag changes at speed.

I guess that's possible, but then I'd expect to see lots of reports of it happening with various Gen 5 models. The Gen 5 also uses a different slide lock/release because it is an ambi, so this could also be a factor. But again, as far as I know it's not a widespread issue with the Gen 5s. Either that or Gen 5 users see it as a "feature", which I do not.

[Trukinjp13]

I guess that's possible, but then I'd expect to see lots of reports of it happening with various Gen 5 models. The Gen 5 also uses a different slide lock/release because it is an ambi, so this could also be a factor. But again, as far as I know it's not a widespread issue with the Gen 5s. Either that or Gen 5 users see it as a "feature", which I do not.

I did not have the auto forward problem. But sometimes we interface differently. Hence the p09 thread. I was just throwing that out there.

[Jim Watson]

Lots of IDPA shooters consider autoforward to be a positive feature, since we must do mostly slidelock reloads.
I have seen them to thump the magazine again instead of reaching for the lever if the slide doesn't close on the reload.
I suspect there might be some mucking about with the bearing surfaces to encourage autoforward.

My Plastic M&P 1.0 is a good autoforward gun, but Smith spoiled that in the 2.0.

My CZ 75 is one of the aggravating ones, it will autoforward most but not all reloads.

[Robinson]

FWIW (admittedly not much), here is something I posted last year in the big-ass Gen5 thread when people were speculating that the Gen5 guns were more auto-forward resistant than previous generations:



I'm just some dude on the internet, and I haven't examined anyone's gun, so grain of salt and all that.

Good info, but this gun will not auto-forward when an empty magazine is inserted so it can't just be the force of the magazine insertion that causes it. The top round has something to do with it. Of course it's possible I don't fully understand your comments.

[HopetonBrown]

Hackathorn demo'd you can get just about anything to auto forward if you vigorously insert mag at a slight angle.

I don't see the benefit, for IDPA or otherwise.

[Robinson]

Assuming the speed of insertion is the same, a loaded magazine will have more energy and transfer more momentum to the loosely coupled slide/frame than a unloaded magazine. Same thing with a magazine loaded with 147s compared to 115s. Basically, you're using a bigger hammer with a loaded mag, or with a mag loaded with heavier rounds.

Also, Inserting the magazine more towards the rear of the magazine vs the front will cause a larger component of the force to be directed towards the muzzle.

I haven't re-read everything in this thread, but many of your more recent posts exactly describe and are in line with the inertial quirk explanation I mentioned. But, like I said, I haven't examined your gun, or your mags, or your reload technique, so there's good chance I'm completely wrong. I don't think am, and if I still got paychecks, I'd bet a paycheck (that I could very well lose, but I'm an idiot about these things) that I'm not. :)

Okay makes sense. How do I fix it? :)

Yesterday when shooting I was being very intentional about how I inserted the magazine during reloads and avoided the auto-forwarding most of the time. But it still happened once or twice. It's not the end of the world but I'd prefer my Gen 5 to act like my Gen 4. The guy at Smyrna said they could try swapping out the slide stop/release assembly for a new one if I want. It's an easy thing to try so I probably will -- but there's no guarantee it won't still happen.

[LittleLebowski]

Okay makes sense. How do I fix it? :)


To be blunt and not trying to be insulting; all Glocks do this, it’s not a problem, and your only fix is to change platform.

[Robinson]

To be blunt and not trying to be insulting; all Glocks do this, it’s not a problem, and your only fix is to change platform.

Really?! I'm not insulted at all, just a bit surprised. My daughter's G17 and my Gen 4 G34 don't have the same thing going on so I guess that's why I'm ignorant about how common it is with Glocks.

I'm becoming more inclined to just deal with it and train in such a manner that it doesn't make a lot of difference whether the slide auto-forwards or not. The gun never fails to load a round into the chamber when it auto-forwards, I just prefer consistency is all.

[Robinson]

Tom_Jones - it just dawned on me it must be the SCD causing the gun to auto-forward. Thanks dude.

j/k

[Robinson]

Yeah it's like 45 minutes without traffic.

[Robinson]

Wow thanks for going to all that trouble. You and (I think) LL have both mentioned pre-loading the slide release and I am starting to work on that as well. I want to train it enough to make sure I won't hit the release too soon and end up with an empty chamber. :)

[GJM]

FIFY


The gun has so far never failed to load a round into the chamber when it auto-forwards, but folks that have done many, many reloads with a Glock and other platforms know that auto forwarding is not 100 percent, and can lead to a stoppage at an inopportune time.

[Robinson]

When done correctly, you don't press the lever with your thumb, but rather the force of inserting the mag causes the the lever to be pressed into the thumb. There are probably lots of posts around here where Todd explained it. There were a couple of posts about 2 weeks ago in this thread about it:

Yeah I remember that thread and my view on the auto-forwarding hasn't changed. I don't mind training myself to deal with it either way, but I prefer that the gun not auto-forward.

LL says deal with it, GJM says it could be a problem waiting to happen. I respect both their opinions. It was a definite problem with the CZ I had because it didn't always load a round into the chamber when it auto-forwarded.

My bottom line right now is training my reloads in such a way that I keep shooting regardless and don't get tripped up by it. But I will still probably take the gun to Smyrna and see if they can get it to stop auto-forwarding.

[Robinson]

Another option is to "preload" the slide release the way Bill Blowers discusses in the video above -- where your thumb sits atop the slide release, but you push into the side of the slide with your thumb, not down.

That is my plan.


Like I said, maybe your gun has some "weird" parts in it. If I were you, I'd take a couple of hours and drive over to Smyrna and see what they say/do. However, it's equally likely this is a technique "problem". Maybe the Gen5 34 just isn't the right gun for you and being in the apparent golden age of handguns, there's no reason to stick with a gun that doesn't work for you. In any case, good luck! Keep us posted. :)

I like the Gen 5 G34 enough that I'm not going to give up on it. I see the problem as something that is almost certainly fixable with a change in method or a trip to Smyrna or both. Especially since its Gen 4 brother doesn't do it at all (so far).