AR woes

[Lazarus]

So a little while ago I posted up saying that my AR was having issues extracting and that rounds were getting stuck in the chamber. The recommendation was to use more lube which I did. So fast forward to today. I went shooting, ran I think 2 mags through it with no problems. First couple of rounds where unsuppressed and the rest suppressed. I loaded up a couple of magazines using the black box American Eagle 5.56 on stripper clips. The magazines are PMAGs.

So I start shooting and the first couple of rounds are fine, then I notice when I pull the trigger it felt kinda soft. Not a strong click bang, more like a thump bang. That happened twice and then the gun didn't fire. I think that might have been a live round. I extract the round, pull the trigger - click bang but the round didn't extract. The bolt was slightly back but it wasn't even far enough back to see the round. So I figured maybe it was a lube issue again which would have been rediculous. I break it down and lube it again with some CLP and put it back together but after that it was the same thing. I could fire the round but would have to manually extract it.

I checked the BCG and the gas rings and they are very loose. I dont remember them being this loose before but I'm not sure if thats the issue or not. I also have a standard buffer and probably need to run a H2. Should I also check the gas block and tube?

 

[mikeyE]

What is your barrel length? Have you ever upgraded your extractor spring?

 

[Lazarus]

What is your barrel length? Have you ever upgraded your extractor spring?

10.5" barrel. No I haven't. Would the extractor spring have bearing on the bolt not moving back?

 

[opps]

Sounds over gassed and under buffered. I run a piston system and H2 in mine.

 

[Lazarus]

Sounds over gassed and under buffered. I run a piston system and H2 in mine.

Yea I'm going to be switching out the buffer.

What about the trigger going soft on me. I thought that was a little weird. It was nice, strong and crisp and then went limp and soft but still fired the weapon.

 

[Dirty J]

This a factory gun?

Home built upper? Lower?

 

[Lazarus]

This a factory gun?

Home built upper? Lower?

No. Its a DSG/Seekins factory upper on a home built lower using Anderson lower, PSA LPK, ACT trigger, Magpul CTR stock with standard mil-spec buffer tube and carbine buffer.

 

[JamesG]

Yea I'm going to be switching out the buffer.

What about the trigger going soft on me. I thought that was a little weird. It was nice, strong and crisp and then went limp and soft but still fired the weapon.

I think that is the bolt and bolt carrier that are not going fully into battery and so the release of the hammer is driving it all the way locked. This would give you that "thunk" when it hung up on whatever it is hanging up on.

I would check your gas tube and make sure its lining up with the piston. Maybe an obstruction in the port?

 

[AO3CoxUSN]

shooting 556 in a 223 barrel ?

 

[Allsmiles]

Check to make sure your hammer spring is installed correctly on the hammer and then make sure that both the spring legs are on top of the hammer. Have you tried this lower on another upper to see if it is working correctly? I've only dealt with an under gassed upper one time and it would only run suppressed. Gas block was drilled incorrectly and replaced. My LR308 was so over gassed that it would throw brass about 20 feet without an suppressor. I put an adjustable gas block on it and solved the issues except that it is slightly over gassed when I run it suppressed. Remember that suppressers don't add gas pressure, just increase the dwell time the gas stays in the system. An adjustable gas block makes things a lot easier to balance as you start with almost no gas and increase it until it functions correctly (and add about 1/4 more turn to screw).