10.5" 7.62x39 AR Feeding issues

cr5 said:
It would have to be measured but you would think that if a company is going to put out a dedicated x39 upper they would do a little research and drill an appropriately sized gas port. I get the impression you believe it to be drilled to the same size as an AR-15, you may be right but if it is I would be very disappointed with that company and their products.
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Like I have stated previously in the thread the 30 caliber AR are notorious for having undersized gas ports. A mid length requires a minimum of .93-.95 and a rifle length needs to be a 1.20- 1.25. I have found that a number of builders get this wrong.

Builders need to forgo altering the buffer weight until the gas system has been optimized for the 30 cal. As pointed out the pressures are more delicate to work with.
 
Poznan said:
SO was it only an ammo issue?
because Im getting pretty much the same result with my norinco ammo and also snap cap dummy rounds when manually charging it.
I have a nea-15 lower
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Have you tried a different lower?
 
bsand said:
Actually the FA bolt would be lighter as the profile has been cut (the one that lets the auto sear engage) while the ar bolt doesn't have a large opening between firing pin and the rear of the bcg so more metal means heavier bolt?
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Actually the FA (m16) is the heaviest of the three types of BC's as it is full length to engage the auto sear as the neutered AR (AR 15 enhanced) semi BC is slightly lighter due to the inability to use it to engage any auto sear and the fully neutered AR 15 (Half Circle) has the entire bottom removed right back to the buffer. The third BC I have described is the lightest of the lot.

There is also an SP 1 that is in between the Enhanced and Half Circle types.

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I hope you figure out the issue, I have to pick up my upper tomorrow from the post office and I have a few hundred czech rounds I was hoping to fire, I plan on running a carbine buffer so we'll see how that works out.
 
There is nothing wrong with the PSA guns, it is ammo and mags...

I had the same issue with the Czech stuff and the mags.
Light extraction with Czech was easily remedied by polishing up the chamber and ensuring it is clean.
Switching it out to other stuff is probably your best bet.

The Mag issue is easily fixed by downloading them to 5-7 rounds - at least until they are broken in.

I'm not a believer of rifle "break ins" as a rule, but give it 600-700 rounds and it should run much better.

...or you could go ripping it apart changing parts unnecessarily and drilling out your gas port:rolleyes: oh, and don't forget to check the headspace:jerkit::popCorn:Laugh2
 
beltfed said:
There is nothing wrong with the PSA guns, it is ammo and mags...

I had the same issue with the Czech stuff and the mags.
Light extraction with Czech was easily remedied by polishing up the chamber and ensuring it is clean.
Switching it out to other stuff is probably your best bet.

The Mag issue is easily fixed by downloading them to 5-7 rounds - at least until they are broken in.

I'm not a believer of rifle "break ins" as a rule, but give it 600-700 rounds and it should run much better.

...or you could go ripping it apart changing parts unnecessarily and drilling out your gas port:rolleyes: oh, and don't forget to check the headspace:jerkit::popCorn:Laugh2
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I never said there was anything wrong with the psa guns I have an upper just waiting on my lower this week and was curious if the OP had solved his issue. I have about 700 rounds of czech ontop of the rest of my copper washed ammo, so sounds to me like I'll be polishing the chamber before I even get out to the range just for good measure.

Yea I figure she'll smooth right out with a few rounds down range, either way its a non-issue for me.
 
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