Tried the search but I'm not too spiffy with it. Anything with info on the upper is what I'm looking for. I have a ar10/lr308 lower that wants to march to a different drum.

From what I can remember, if you are talking about a DPMS model, your lower will only accept a DPMS upper so you will be looking for availability of DPMS parts.

I have a PSA lower, believe is says PT10, P-TAC. Mainly wondering about bolt, mags and thoughts on who's barrel.

PSA makes a 7-08 upper. Problem solved.

If you have a PA10 lower you need to stay with PSA stuff. For some odd reason they made a lot of their parts proprietary.

This is a direct quote from PSA from ARFCOM



Also the uppers and lowers are not AR10/LR308 compatible a PSA PA10 upper will not fit on a DPMS/Armalite lower vise versa with PA10 lowers and DPMS/Armalite uppers.

I had looked at PSA but their only 7mm-08 has a 20" barrel. I was thinking 16" maybe 18". I don't mind using a PSA upper, I think they are fine. Any problem with the lengths I'm thinking of?

on my list next is the bolt, I'm lead to belive the .308 carrier will work but what about the bolt itself?

The bolt will be same as a .308 (7mm-08 is a necked down .308, right?).

Some AR barrels come with "headspaced" bolts, which means the barrel maker supposedly checked that the bolt was in spec.

Some drop in AR barrels do not come with bolts, but should headspace fine with a proper in spec bolt.

Does the PSA upper not come complete with BCG? If the PSA stuff is proprietary I'd think they'd have one available with the upper.

DPMS patten upper will fit on a PSA PA-10 lower. I put one together in 308 using the DPMS upper.

Then they have changed them, that was a quote from the psa rep on arfcom in reply to a customer complaining that it didn't fit.

So the next big decision is barrel, length and mfg. If you have one, what length is it and is there any reason not to go with a shorter barrel?

I don't know about manufacturers, but if you aren't running a suppressor/brake/hider I'd go at least 18".