Need help from you AR 'smiths-NTK possible headspace issues..

[DisgruntledReaper]

Hi Guys, i need input on AR15 headspacing issues and here is the setup-
I basically cannot see why you would buy an upper WITHOUT a matched BCG seeing as I have heard that if your headspacing is off you basically have to go through bolts till you have a correct one-is this crap correct!? I am used to FAL and HK/CETME where you can make adjustments to other parts in order to get the HS correct...

Reason i need to know- I just bought a like new(300rds)Bushmaster Dissipator A2 upper with a KAC M5 RAS BUT without the BCG for $416 shipped off of AR15.com......guess it is a good deal BUT now I need a bcg and am worried that getting the HS right may be a PITA unless 'milspec' also includes the HS staying close enough to 'std'(?) so it is not much of an issue.

I hate headspace issues.....

Can you guys give me input on what BCG I should go for-like get a BM or will basically any from the better known mfr's work....I dont want to have to go through bolts til I get it right....$$$would get ridiculous I think.

Anyway please give me your experiences and if anyone has a good used bcg for possible sale please pm me.

Thanks!

[xsquid]

From arfcom "You can’t really reset the headspace on an AR15 with a chrome-lined chamber. That is set when the barrel extension is installed on the barrel. If you have an unlined barrel, with short headspace, a gunsmith can adjust it by cutting the chamber deeper with the appropriate chambering reamers. If the headspace is long, or the chamber chrome-lined, the only option is to try a different bolt until headspace checks good, or you run out of bolts. Then it is time for a new barrel."

Your barrel with 300 rounds thru it is practically new. I'd get a new bolt, check with a field guage - and blast away.

[slick_711]

The AR is one of the most modular rifle systems on the planet. And you're worried about this before even putting a BCG in it? Any mil-spec BCG should be fine, but you may as well get a BCM. Drop that in there, toss in a go/nogo gauge, and go shoot.

It's rare to have a headspacing issue with an AR that was put together properly with mil-spec parts. If you do have such an issue, yes, it sucks... but it's pretty rare.

[CHS]

5.56 has extra headspace anyways. Don't worry about it.

[ar15barrels]

I just bought a like new(300rds)Bushmaster Dissipator A2 upper with a KAC M5 RAS BUT without the BCG for $416 shipped off of AR15.com......

The first thing to know is that ALL round counts advertizes on used barrels are under-stated, usually by a factor of 10x.
The next thing to know is that ALL round counts made by shooters online are over-stated, usually by a factor of 10x.