AR Sponsor
Posted: 2/16/2017 10:09:55 PM EDT
I recently finished my 9mm AR build and put 250 rounds through it. Gun is running great. Not a single hiccup, good accuracy and quick handling. Came home and to clean it and inspect things over. This is what I found, the buffer is smashed in and the quarters I used for spacers top coin is dented. 
Honestly I'm surprised it didn't malfunction. I'm running a carbine extension with milspec buffer and spring + 7 quarters. I guess I need less in there. Anyone else experience this type of damage before? Guess ppl are not kidding 9mm ARs are rough lol. 
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Milspec buffer?
Ouch. Those are one of those cheap lightweight buffers that come with those 6061 tube kits. You need to be at least at an H3 buffer. I highly suggest the KAK 10oz buffer (Actually weights 10.9oz): https://www.kakindustry.com/ar-15-parts/lower-parts/buffer-tubes-and-parts/pistol-buffer-tubes/ar15-9mm-buffer-long-heavy |
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To me, that looks more like a POS buffer made of wrong material. It didn't stop functioning or make any unusual sounds? I can't imagine how the spring could move over the buffer without binding and causing all kinds of issues.
I've run a standard mil-spec ~3oz carbine buffer and never had one end up like that. 5-5.5oz is all you need for SA non suppressed. |
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Quoted:
No, do not use an extra power spring with a blowback 9mm. Depends on what loads your using & buffer weight, on my 16" with an 8.5oz buffer a Wolff xtra power spring is great with +P ammo but chokes on light loads. But overall a std. weight spring runs OK with everything. An xtra power spring will put more stress on your bolt catch. If I was strictly running hot loads I'd upgrade to a 10 oz buffer before going to a stronger spring. On my rifle the heavy buffer & xtra power spring had more felt 'recoil' when the buffer slammed home than when it came back. IMHO 5 oz is the minimum weight for a 9mm blowback. I don't know of any manufacturer of one that comes with less. |
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In no way shape or form is spring power a substitute for reciprocating mass in a blowback system.
The main function of extra power springs in a 9mm AR is to beat the crap out of the firearm, as illustrated in two different threads just this week. It takes very little energy to strip a 9mm from the magazine and chamber it in a 9mm AR. That's what the spring does. |
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Quoted:
In no way shape or form is spring power a substitute for reciprocating mass in a blowback system. The main function of extra power springs in a 9mm AR is to beat the crap out of the firearm, as illustrated in two different threads just this week. It takes very little energy to strip a 9mm from the magazine and chamber it in a 9mm AR. That's what the spring does. This. Mass keeps the bolt closed, and has an order of magnitude more effect on the initial bolt velocity than the rate of the spring. You just need a spring that is strong enough to strip and chamber without being sluggish. |
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