ar15 pistol ejects but doesn't lock open or load

Discussion about rifles in 300 AAC BLACKOUT (7.62x35mm), hosted by the creator of the cartridge.

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JoshInPNW
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ar15 pistol ejects but doesn't lock open or load

Post by JoshInPNW » Fri Jan 07, 2022 6:15 pm

I am running an H2 buffer on a piston driven AR15.
I read a few threads that said "get an H2 buffer" - but I am already running an H2 buffer.
The gas block is set correctly (distance from shoulder)
Ejects empty cases, but won't strip a round off the magazine. It doesn't lock open on "last round" either.
I read some posts about making the gas port bigger (on barrel); but this came with caveats about doing it, I'm willing to drill it out, but don't want to just blindly drill anything.

My gas block is an adjustable one, but it is set to 100% right now (yes, I tried lower settings).

Ideas ?

Thanks

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ReadyAimDuck
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Re: ar15 pistol ejects but doesn't lock open or load

Post by ReadyAimDuck » Fri Jan 07, 2022 9:39 pm

First, what are you using for ammo? Subs, or supers? Factory loads?

When the bolt doesn't lock back on an empty magazine, you're likely not getting enough gas pressure to push the mass of the BCG, buffer, and overcome the force of the spring. So, you would want to try a lighter buffer at that point. Not a heavier buffer like an H2. Do you have a carbine buffer you can swap in?

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gds
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Re: ar15 pistol ejects but doesn't lock open or load

Post by gds » Sat Jan 08, 2022 8:45 am

Piston driven has its own set of problems.

Not enough information.
Type of ammo, like readyaimduck said would be helpful.
Barrel length
gas port location, ie. pistol, carbine, midlength, rifle.
suppressed/unsuppressed

Most answers I would have would be directly related to typical direct impingement. Just a guess, but i think I would try a standard buffer before I did anything else.
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JoshInPNW
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Re: ar15 pistol ejects but doesn't lock open or load

Post by JoshInPNW » Tue Jan 11, 2022 6:13 am

Thanks!

Shooting some 125g sig saurer super
barrell is 10.5"
pistol length gas system

I'll give a standard weight a try when I get a break in the rain.

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