do i need to have a new bolt headspaced?

[jriggs]

I've never had to think about this before and I've never come across the topic...but if I decide to swap out the standard carrier/bolt for a low mass unit from JP....should I have the new bolt headspaced for my Shaw barrel? is that necessary?

thanks in advance,

riggs

[67camaro]

Yes, either that or use your old bolt in the new carrier.

[openclassterror]

Technically speaking, if the barrel is mil-spec, and the bolt is mil-spec, it will fall within the 5.56 headspace range. However, the NO-Go(max) gage for 5.56 is the same dimension as a FIELD(unsafe to fire) gage for .223rem. It is IMPERATIVE to know the specs on all the parts. If you don't have the information, a headspace check is a must. Just make sure your gunsmith uses the correct gage set for your chamber. (IE .223 OR 5.56mm, depending on what the barrel is marked). If it says .223/5.56, that is a misnomer. It can't be both, so this usually means it is the bigger of the two. Ironically, the GO(minimum) gage dimension is the same, it is only the max allowable gage size that is different.

[jriggs]

ok thanks for the info....what I have is the ER Shaw 5.56 barrel off my Stag 3G in a JP CTR upper....and I've put a JP adjustable block on it and was toying with the idea of just snagging the low mass carrier/buffer/spring to finish things up. I figured it would be easiest to just order the carrier without the bolt and just swap the one from my Stag but was curious about headspacing if I desired to just order the compete carrier/bolt from JP