Gunsmithing new upper and old BCG

[Zachary Rehbein]

Guys.

I just bought a new upper receiver from DSarms. It did not come with a bolt carrier group. Can I use an old one from another AR with it, plug and play, or do I need to get this barrel and Bolt head spaced properly? Thanks for the help!

 

[dang472]

Theoretically, everything should be good to go. I've been able to buy a used barrel and use my old BCG and everything worked fine. Assuming you are using the same barrel and BCG, just replacing the upper receiver, used should be perfectly fine. Most precision barrels are sold with a headspaced bolt and the upper has nothing to do with the set as long as you're using an in-spec receiver.

 

[Zachary Rehbein]

its a new 16" barreled upper a different company's BCG? should I buy or get a gunsmith to run a go/ no-go gauge through it?

 

[dang472]

It's always advisable to run a go/no go gauge through any new barrel install in the rare chance it was chambered wrong. I personally would run it as long as the used BCG isn't hammered and possibly out of spec. Brownell's has a 5.56 field gauge for $22.99. If you want to do it right, grab one of those and have the piece of mind.

 

[303_enfield]

Couple of bucks more then a no-go gauge you can buy a new bolt. Get a new bolt and use the old carrier. As for buying headspace gauges, are your cambers 5.56 or .2233 Rem? Cheaper to rent or borrow the right gauge for one or two uppers.

Heck, a new bolt can fix bad headspace on an old barrel for the short term.

 

[Zachary Rehbein]

All very helpful thanks guys. i'll probably just go to a gunsmith in Missoula and have them check it really quick.