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, 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.
I think LL ran one for a spell, should have some good info for you.
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.
#RESIST
Well, get it posted, dude; I'm about to whine about this at VFTP and I need something to link to.Originally Posted by LittleLebowski
Might be a few hours or a day. Hold fire and bug me as needed.
#RESIST
I am the very soul of patience.
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.
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.
5.45 is also no joke at short ranges. Ammunition selection dependent, of course.
I was kinda wondering about the magazines, thanks!
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...
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