Gunsmithing bolt/barrel questions from a noobie

[NCHillbilly]

I am in the process of building my first gas gun from the ground up. It will be a 308 based on the DPMS gen 1 design. I am currently gathering the parts for this build, but have a question. I am ready to get the bcg, and was hoping to run a toolcraft or JP bcg. I have already bought an 18" BA barrel, and wondered this: If I get a toolcraft or JP bolt, will I have to have a smith set my headspace to the barrel I currently have, or if I bought a BA bcg, since it is the same brand as the barrel, would it too need to be set or would it be a drop-in affair. I know (or have been told) the 308's are more finicky about mixing different brands of parts.

 

[stompbox]

You can have a smith check the head space of your barrel and bolt to see if it is good. But to actually set it, if it is out, is a whole other process and not really practical unless they can just ream the chamber deeper, if it is short. If the bolt closes on a NO-GO, check with a field gauge.

 

[2aBaC̶a̶]

What stomp said.

To elaborate, when you buy a barrel for an AR type rifle the headspace is all predetermined when they make the barrel. There is really no changing it once it's made.

99 out of 100 times brand A's bcg will function in brand B's barrel. Buying from the same manufacturer further guarantees it will fit and tolerances most likely tighter.

 

[NCHillbilly]

What stomp said.

To elaborate, when you buy a barrel for an AR type rifle the headspace is all predetermined when they make the barrel. There is really no changing it once it's made.

99 out of 100 times brand A's bcg will function in brand B's barrel. Buying from the same manufacturer further guarantees it will fit and tolerances most likely tighter.

I knew that to be the case with AR-15's, but wasn't sure about the AR-10/LR-308 platform. With this being my first ground-up build, I just wanted to be sure.