View Full Version : Headspace

kris smith
03-05-2012, 3:26 PM
Reading some stuff on head space has gotten me worried I bought a model 1 upper off a fellow cal gunner last year and it came with a bcg that he had laying round should u be worried about head space or just rock it ?

03-05-2012, 3:39 PM
If the bolt locks in the extension with a round chambered it is gtg.

03-05-2012, 4:14 PM
If you've shot it and it hasn't blown up yet I'd say you're doing well.

Strictly speaking it should have had the headspace checked. Any time you mix and match barrels and bolts there is the possibility that the parts will be on the opposite end of tolerance. That could lead to chambering problems on the tight side or "spontaneous vigorous dissassembly" on the other. Many people think that because the sh*t they buy is "mil-spec" that it's all good. That's not the case. Headspace gauges are cheap...how much are your eyeballs worth.

Sorry that's kinda heavy, but it's a pet peeve of mine.

kris smith
03-05-2012, 4:27 PM
No problem I can handle heavy my eyes are worth a lot I haven't shot it in its current set up

03-05-2012, 4:31 PM
NATO 5.56 chamber: go gauge: 1.4640. no-go gauge 1.4706.

I tested several factory ammo (PMC and Fiocchi), most of them are at 1.4636-0.004 = 1.4596. So it's not exact go gauge, but close.

If you bought the complete upper, it should be gtg.

kris smith
03-05-2012, 4:38 PM
It was complete but it was a bcg he ha extra I Dont Know I he fired it as was sold or not