AR47 Build on GWACS Armory CAV-15 MKII Lower

[Emptymag]

I took it to the group shoot today and forum member USMCbunchanumbers brought along a heavy weight hammer spring for me so I switched out the ALG Defense ACT hammer spring for the Wolf hammer spring.

No different - primers hit, but no ignition. (Tula and some old, green lacquer Wolf)
Probably 3 out of 5 rounds.
I forgot to bring brass to try.


I guess I still need to tweak the gas block too because I think out of 15 rounds it only stripped another round from the mag and chambered it twice - each other shot that actually fired failed to load the next round. (and it was working when we first set it up last weekend)

[Emptymag]

Anyone have any thoughts on what I should try next?

Much of what I've read suggests that there are only two issues with steel case ammo not firing - the firing pin, or the hammer spring.

Since the firing pin I have is supposedly an "enhanced" firing pin and the Wolf extra power hammer spring didn't help, now what?

Should I try a different brand of firing pin?

[JDA58]

USMC (bunch of numbers) said He has a big pin.... or something like that.... I'm guessing he was talking about the firing pin

[JDA58]

for real... not fucking with you

[gghbi]

I guess I still need to tweak the gas block too because I think out of 15 rounds it only stripped another round from the mag and chambered it twice - each other shot that actually fired failed to load the next round. (and it was working when we first set it up last weekend)

Now that everything is nice and dirty, this may be true.

Have you inspected the firing pin since this problem started? Sounds like the prime suspect. I want you to succeed in finding the problem.

(I am considering a build and like having someone else be the test subject.)

[ViperHummel]

Anyone have any thoughts on what I should try next?

Much of what I've read suggests that there are only two issues with steel case ammo not firing - the firing pin, or the hammer spring.

Since the firing pin I have is supposedly an "enhanced" firing pin and the Wolf extra power hammer spring didn't help, now what?

Should I try a different brand of firing pin?

It's not just about the firing pin. If the bolt rail is too long or the firing pin hole isn't large enough, Then the firing pin isn't going to get the deeper strike that it's supposed to. An enhanced firing pin and "shaved" bolt tail can cause popped primers.

You could try a Red X Arms or Black Rifle Arms firing pin. Can you post pics of the bolt with the firing pin "bottomed out"?

This is a way older pic from a while back when I sold the upper, but this is a 7.62x39 bolt with me holding the firing pin in the "bottomed out" position.

76239 bcg e firing pin.jpg

[Emptymag]

It's not just about the firing pin. If the bolt rail is too long or the firing pin hole isn't large enough, Then the firing pin isn't going to get the deeper strike that it's supposed to. An enhanced firing pin and "shaved" bolt tail can cause popped primers.

You could try a Red X Arms or Black Rifle Arms firing pin. Can you post pics of the bolt with the firing pin "bottomed out"?

This is a way older pic from a while back when I sold the upper, but this is a 7.62x39 bolt with me holding the firing pin in the "bottomed out" position.

Thanks. I'll grab a photo tomorrow. Dealing with plumbing problem at moment. Yay.

[iMoses14]

I took it to the group shoot today and forum member USMCbunchanumbers brought along a heavy weight hammer spring for me so I switched out the ALG Defense ACT hammer spring for the Wolf hammer spring.

No different - primers hit, but no ignition. (Tula and some old, green lacquer Wolf)
Probably 3 out of 5 rounds.
I forgot to bring brass to try.


I guess I still need to tweak the gas block too because I think out of 15 rounds it only stripped another round from the mag and chambered it twice - each other shot that actually fired failed to load the next round. (and it was working when we first set it up last weekend)

The 7.62x39mm AR can be a pain. Make sure your bolt face and chamber are both the same. Your bolt can be either .125" or .136" face depth. Barrels are made to accept one or the other. This will cause issues if one of them is different regardless if you have a extended firing pin, heavy hammer spring, H2 buffer or reduced disconnector / trigger springs.

[Emptymag]

The 7.62x39mm AR can be a pain. Make sure your bolt face and chamber are both the same. Your bolt can be either .125" or .136" face depth. Barrels are made to accept one or the other. This will cause issues if one of them is different regardless if you have a extended firing pin, heavy hammer spring, H2 buffer or reduced disconnector / trigger springs.

I have no idea what "size" either are. No specs for either the barrel (PSA) or the BCG (APOC Armory) regarding .125 or .136

[Emptymag]

Got a few pics. Will post this evening after work.