Head Space on upper?

[fguerra]

I purchased a LMT upper along with the bolt, carrier, and charging handle. Since LMT doesn't sell them as one , should I get the head spacing on the upper checked? Everything is LMT including the lower (not that the lower should matter).

Thanks.

[superhondaz50]

From what I know a new upper with a new bolt carrier assembly doesn't need to be head spaced. From what i've heard headspacing on a AR is not an issue when new because neither parts are worn yet. On AR's head space is pretty much universally set at the factory, and is part of the strict tolerances that are met when an upper is put together. Dont quote me on this but a new upper and new BCG is a go, old upper with new BCG is a go, new upper with old BCG is a go, but a old upper with and old (non-matched) BCG is a no-go, and requires headspacing. This is what I've heard over the years, but maybe someone with a little more knowledge on headspacing can chime in. FYI I put a new DPMS BCG into an old USGI upper with no headspace check and have fired 500 rounds through without any problems.
Good luck

[mltrading]

I purchased a LMT upper along with the bolt, carrier, and charging handle. Since LMT doesn't sell them as one , should I get the head spacing on the upper checked? Everything is LMT including the lower (not that the lower should matter).

Thanks.

What are you talking about? All upper halves from LMT have been test-fired and headspaced prior to shipping, even though you buy an upper half without BT/BC.

For AR platform, the headspace is determinated while barrel extension being installed. And remember to use true mil-spec BT/BC. There should be no problem.

[ocabj]

While it is true a brand new bolt and a brand new barrel should headspace fine, there is always the offchance that the headspace not correct. How big a chance? Maybe less than 1% of 1% of the time. It's not a big risk, but a risk nonetheless.

A used bolt on a new barrel, a new bolt on a used barrel, or a used bolt on a used barrel is another question. Those should definitely be headspaced.

[Pthfndr]

I purchased a LMT upper along with the bolt, carrier, and charging handle. Since LMT doesn't sell them as one , should I get the head spacing on the upper checked? Everything is LMT including the lower (not that the lower should matter).

Thanks.

In YOUR particular instance, don't worry about it. Everything will be ok.

[fguerra]

Thanks for the replies guys. Better safe than sorry, you know. Spent $1200+ on the complete upper and would hate to break it. Now it's time for BUIS and maybe an Aimpoint.