5.45x39 in an AR...

[Tamara]

Anybody have much experience with running the smaller commie round through AR carbines?

You'd think that, having lived through the Great Ammo Drought of '08-'09 and owning a switch-barrel carbine (http://pistol-forum.com/showthread.php?2787-Takedown-guns&p=46257&viewfull=1#post46257), I would already be a fount of information on this topic, but it took noticing that the only reasonably-priced rifle ammo on the market right now is 5.45 to make the little light come on over my head.

[JM Campbell]

I think LL ran one for a spell, should have some good info for you.

[LittleLebowski]

I have a blog article that is mostly finished, want that or got something specific? I've got over 24k rounds through mine and a few carbine classes under my belt with it.

[Tamara]

I have a blog article that is mostly finished...

Well, get it posted, dude; I'm about to whine about this at VFTP and I need something to link to. :D

[LittleLebowski]

Might be a few hours or a day. Hold fire and bug me as needed.

[Tamara]

Might be a few hours or a day. Hold fire and bug me as needed.

I am the very soul of patience. :cool:

[LHS]

I have very limited experience with 5.45mm carbines, mostly through a friend who seems to get his rocks off by building the weirdest gun/caliber combos he can conceive (he has TWO 7.62x25mm 1911s...)

His 5.45mm 8" AR SBR seems to run fine in terms of gas system, but the hard primers on the Russian surplus ammo are a definite problem. He's had to put in a heavier firing pin and a more powerful hammer spring just to get some kind of reasonable reliability. Otherwise, it'll be about 50/50 with light strikes. It runs a lot better with commercial 5.45mm, but that's getting harder to find and more expensive.

That said, the gun's a complete frankenbuild, so who knows how much of that is tolerance stacking (it's entirely possible the hammer's movement is retarded, god only knows what kind of parts he threw into it), but my money's on the hard primers.

[Jay Cunningham]

In my experience they run well and are accurate, and they simulate the recoil impulse and trajectory of 5.56 close enough. On the down side there's no specifications for components, so tolerances may vary. You'll probably need to keep your chamber a little cleaner (and clean the rifle a little more in general) and you may need to actually tweak the gas system a little for optimal performance. You also get the occasional weird keyhole which is just inherent to the 5.45mm round. Magazines are not that great, and no, trying to use 5.56mm magazines is not a good solution.

[Odin Bravo One]

5.45 is also no joke at short ranges. Ammunition selection dependent, of course.

[Tamara]

In my experience they run well and are accurate, and they simulate the recoil impulse and trajectory of 5.56 close enough. On the down side there's no specifications for components, so tolerances may vary. You'll probably need to keep your chamber a little cleaner (and clean the rifle a little more in general) and you may need to actually tweak the gas system a little for optimal performance. You also get the occasional weird keyhole which is just inherent to the 5.45mm round. Magazines are not that great, and no, trying to use 5.56mm magazines is not a good solution.

I was kinda wondering about the magazines, thanks! :o

Regarding the comments about hard primers on milsurp 5.45 and gas-handling issues, I'm not willing to make changes to a lower or bolt carrier that has been stone-axe reliable with 5.56. The biggest advantage to the MGI QCB system is that it uses standard AR barrels and therefore the gas-handling system is portable with the barrel. If I can get a centerfire alternate that is roughly comparable in reliability with my M&P 15/22, I'll count it as a win...

[Jay Cunningham]

I had to use the heavy hammer spring that came with my S&W upper. I tried without and it wouldn't detonate primers 80% of the time. With the heavy spring, no issues but the trigger is pretty stiff. Certainly not unworkable though.

[Chemsoldier]

Where are you seeing 5.45 for sale? My previous source sold out a month ago.

[Jay Cunningham]

Its available here and there.

http://www.ammunitiontogo.com/index.php/cName/545x39-military-surplus

[LittleLebowski]

Now accepting heckling and jeering..... Seriously, lemme know what I missed or screwed up.

http://rationalgun.blogspot.com/2013/01/my-definitive-545x39mm-ar15-article.html

[Kyle Reese]

Great article. I personally witnessed how accurate LL's 5.45mm AR was at Defoor's Carbine class at USTC in April of 2011. The guns are accurate with Soviet ammo, given the end user does his/her part.

[Jay Cunningham]

Nice article.

I would be wary of anyone jumping to the conclusion that they have a "bad" or "shot-out" barrel if they see rounds hitting sideways (keyholing). I believe it's a characteristic of the 5.45mm round, and is not very predictable.

My best guess is that *within a certain lot of ammo* you may have some that will have an early shift of the bullet internals. I believe this leads to 5.45 KHing, though I'm sure a shot-out barrel could contribute. One question: what was long-range accuracy like at the 12,000 round mark?

In regards to magazines, I personally replaced the weak, short springs with cut-down AK-74 mag springs. This has increased reliability. No I did not cannibalize actual AK-74 mags, I contacted a vendor and they sent me some springs.

[LittleLebowski]

Nice article.

I would be wary of anyone jumping to the conclusion that they have a "bad" or "shot-out" barrel if they see rounds hitting sideways (keyholing). I believe it's a characteristic of the 5.45mm round, and is not very predictable.

My best guess is that *within a certain lot of ammo* you may have some that will have an early shift of the bullet internals. I believe this leads to 5.45 KHing, though I'm sure a shot-out barrel could contribute. One question: what was long-range accuracy like at the 12,000 round mark?

In regards to magazines, I personally replaced the weak, short springs with cut-down AK-74 mag springs. This has increased reliability. No I did not cannibalize actual AK-74 mags, I contacted a vendor and they sent me some springs.

Good point. I'll edit it to point out that random keyholing can happen but mine was absolutely indicative of a shot out barrel. I tried three different types of ammo after I first noticed the keyholing (at a SoVA VMI-MO range day, no less).

I noticed no degradation in "long range" (300 yards and in due to my local geography) before the barrel got worn out. This was on torso sized targets; at least one forum member (keydet08) has shot next to me when I was using my 5.45 at 300 yards.

[Jay Cunningham]

Did you use the Hornady ammo, or did you use three different types with the "air pocket"?

[LittleLebowski]

Did you use the Hornady ammo, or did you use three different types with the "air pocket"?

Wolf, Hornady, and a different lot of Sov surp. The rounds spinning sideways hit the dirt in a most impressive manner :D

[LittleLebowski]

Great article. I personally witnessed how accurate LL's 5.45mm AR was at Defoor's Carbine class at USTC in April of 2011. The guns are accurate with Soviet ammo, given the end user does his/her part.

Aye but I believe your KAC SR15 had a slight edge in accuracy. That was a good class.

[LHS]

Twist rate also comes into play. Iirc, the AK74 has a 1in8 twist, while the short barrel guns like the AKSU have a 1-in-6 twist. I know BlueJack did a limited run of 5.45mm AR barrels with the correct twist and groove pattern a while back, but they're hard to find.

[Ed L]

That was an awesome article, LL!

Nice work.

[LittleLebowski]

That was an awesome article, LL!

Nice work.

I'll take that compliment and thank you!

Sent from my Nexus 7 using Tapatalk HD

[rudy99]

With the current ammo situation and the discovery of gunbot.net and wikiarms.com, 5.45 is becoming more appealing to me. I'm having a hard time finding uppers for this caliber for sale (obviously finding them in stock is another issue). The S&W (http://www.smith-wesson.com/webapp/wcs/stores/servlet/Product4_750001_750051_764984_-1_772656_770653_757964_ProductDisplayErrorView_Y) website indicates their 5.45 upper is no longer in production.

Here are the options that I've found thus far:
Spikes (http://www.aimsurplus.com/product.aspx?item=xstu4260mls)
Model 1 (http://www.model1sales.com/index.cfm?fuseaction=category.display&category_id=282) :(
Adam Arms (http://www.rainierarms.com/?page=shop/detail&product_id=1893) Piston :(
Huldra Arms (http://www.huldraarms.com/uppers/product_76b374d367d8/) Piston :(

Anyone know of any decent manufactures that are making 5.45 uppers? Spikes is the only one in the list above that looks decent.

[LittleLebowski]

I'd go Spike's then Huldra.

[Chris_S]

I picked up one of the Spike's 5.45 uppers a few months ago when they were in-stock at AIM and I'm still waiting to see how it will be long term. I've put about 400 rounds through it in 3 range trips and, right around the 100th round I had a pretty spectacularly stuck case. I'm hoping it proves to be a fluke.

When shooting, the rifle feels like my 5.56 guns except for the slightly heavier trigger pull and, really, the weight from the heavy hammer spring is only going to be an issue if you're used to doing all of your shooting with hair weight set triggers. Hosing it out with water after each range trip is a bit of a pain but, so long as you follow LL's instructions on that, you're shooting a centerfire AR for $0.18 a round during a panic and not dealing with any corrosion issues. It's absolutely worth the hassle.

[Sadmin]

Agree that its worth the squeeze. I have been following LLs progress with the caliber in an AR for awhile on M4C and picked up a s&w, adams, and spikes. The Adams upper has been the most problematic. I cant pinpoint any specific besides its just flat our inconsistent with reliability.
If I was starting from scratch, I would get one of the BA barrels and have an upper built. RCA stated they would begin production on 5.45 bolts at some point as well.
Mags are all ASC with 3 of the modded window PMAGS which work fine if your into cutting up followers...I would rather just have the ASCs.
I have been using the S&W so often now with no issues, I put my SD-C trigger in it and the stiffer spring on it works great. No light primer strikes; its a bit like putting a silk hat on a pig but I actually might stick to the round since its still pouring in at an affordable price. USAC just updated stock this morning.

[LittleLebowski]

With the ASC mags being available (even in these times), I see no need to modify other mags.

[Doug]

Nice article.

In regards to magazines, I personally replaced the weak, short springs with cut-down AK-74 mag springs. This has increased reliability. No I did not cannibalize actual AK-74 mags, I contacted a vendor and they sent me some springs.

During classes, I have had mag issues I thought were attributable to weak springs.

Would using Wolff power springs for AR15 have the same result instead of cutting down AK 74 mags?


http://img.tapatalk.com/d/13/05/16/e4unapy3.jpg

http://www.gunsprings.com/index.cfm?page=items&cID=2&mID=1&dID=79

I need to disassemble the ASC mags to check and compare spring length 5.45 vs 5.56.

They have extra power AK74 mag springs also.

http://www.gunsprings.com/index.cfm?page=items&cID=2&mID=141

[Kyle Reese]

I really regret not purchasing a S&W M&P 15 in 5.45x39 when they became available in 2008/2009. LL's 5.45 AR performed very well at a KD class a few years ago at USTC, and it (with the ASC mags) had no issues during this course.