308 build question

[joseph92]

hi im new here but not new to ar-15's, but new to the ar 308 platform 

i read on another post here that a dpms barrel will work with a armalite receiver as long as the bolt carrier is a dpms as well.  i am starting to build my first 308 ar and havent really started building anything just really messing with the new parts that came in.  i have a dpms barrel and a dpms bcg but i am using an armalite receiver. my question is when i attach the barrel to the receiver and insert the bcg and charging handle, i have to push the charging handle and bcg some what hard and when the charging handle and bcg are flush in the rear of the receiver, the bolt twists from the bcg being pushed forward.  is that normal?

thanks

[Jgun]

Not sure if I understand you correctly, but the components for the .308 platform are basicaly the same as for the .223, just scaled up in size. So, if you install the charging handle in the slot (without the bolt carrier group installed) does it slide back and forth without binding when it latches in the closed position? Next, since the bolt cams on the barrels locking lugs in the same way as an AR 15, it rotates in a counterclockwise direction (when viewed from the back) when it locks up. You might want to check to see that the bolt will cam in the carrier while in your hand out of the gun. My DPMS chromed BCG was very stiff when it came in the mail and didn't loosen up until I put 100 rds or so through the gun. Maybe the twisting you describe is the  bolt resisting the caming action and the carrier trying to twist the opposite way. Is the carrier when viewed from the rear held upright, twisting in a clockwise direction? You would definitely be smart to check your headspace on this build before firing the gun.

[madcratebuilder]

i have a dpms barrel and a dpms bcg but i am using an armalite receiver.

I believe the barrel nut threads are a different, I've read both interchange, and that they do not interchange, something about the barrel extension being longer on the AR10 and causing a feed issue.

[imschur]

Yes the Armalite and DPMS receivers have  different barrel nut thread. The bolt regardless of the carrier used much match the barrel extension type.