AR .308 Buffer issues

[Scotts]

I just completed my .308 build, I used DPMS pattered 80% lower Aero upper 24” barrel. I fired it for the first time and the bolt won’t pickup the next round and also won’t lock open after firing the last round in the mag. I used rifle length gas system with a .308 rifle buffer & spring. My question is should I go to a .308 carbine buffet? To solve this problem?

[Scotts]

[jtallen83]

You should not need to swap anything in the recoil system as long as they are 308 AR rifle buffer and rifle spring.

I'd check the gas system, maybe misaligned gas block? Can you post a picture of the gas tube end in the upper, from bottom of the upper, straight above the end of the tube.

Could be it needs more lube and more rounds, lots more surface area to mate on these big frame rifles.

[Scotts]

[Matt.Cross]

7 minutes ago, Scotts said:

That's part of your problems right there. That tube should end close to the center of the cam pin cutout.

[Scotts]

This is my first.308 build so forgive me for stupid questions. Am I missing something? It’s a rifle length tube, are you saying it’s too short?  is there a longer one? 

[jtallen83]

3 minutes ago, Scotts said:

This is my first.308 build so forgive me for stupid questions. Am I missing something? It’s a rifle length tube, are you saying it’s too short?  is there a longer one? 

Yes, the Armalite AR-10 rifle length gas tube is longer. If you search for it here you will find others with the same fix needed.

https://www.armalite.com/product/10007010-ar10-rifle-length-gas-tube/

Edited May 23, 2019 by jtallen83
link

[Scotts]

Thanks a lot for the reply! I’m gonna order one right now. 

[jtallen83]

12 minutes ago, Scotts said:

Thanks a lot for the reply! I’m gonna order one right now. 

Measure what you have. Chances are it is AR-15 rifle length but you never know with these things.

[Scotts]

Will do, thanks again you were a big help.