I have had a AR 10 since 2012 and I bought a number of P-Mags for it at that time, then I found it could only use Armalite metal Mags so I got some of them.  Armalite had a sale on a collapsible stock so I bought it and then they said I would need a different buffer.... okay I finally got one, but Areo Precision then come up with a stripper lower and I got it.  I am just gathering parts right now, but instead of building a whole new rifle right away, I was wondering if I could put the Armalite Upper on the DPMS style lower for awhile?

Nope,won't work.

I think backbencher figured out some way to make it work. I'll send the link for this th read to him so he can chime in.

IIRC there will be a gap between the receivers because the Armalite has the angled AR-10 style cut to it while the DPMS has the rounded AR-15 style cut to it. Also there is some milling that needs to be done to the interior of the Armalite to get it to work. With has many affordable DPMS styled receivers out there it's not worth the hassle IMHO.

Yeah I figured something that seems simple...... I do not want to modify anything.  It will just take more parts and time.

I think it was AR15barrels of AR15Barrels.com that figured out how to make it work & did one years ago.  There will be a gap @ the rear of the upper, due to the straight angle of the Armalite upper and the curved receiver extension boss of the DPMS lower.  Also, the magazine stop ribs on the inside of the upper will need to be milled out.

This is one of his earlier threads:  http://www.ar15.com/forums/t_3_121/265951__ARCHIVED_THREAD____More_AR_10_and_DPMS_compatibility___.html

It was the magazines lips that were my only concern. I wasn't intending to carry the rifle in a tactical training environment.  Just in the pickup.  I like the Armalite too well to mess with it.

I could just put the Stock and JP buffer on the Armalite, but why do that when I have a excellent excuse to build a new 308

The least expensive route to a functional .308" AR receiver I'm aware of:

http://www.theflatspot.net/308-receiver-flat-dpms-style-like-ar-10.html  $33 + $6 flat rate shipping.

Thanks for that link.  I can afford it just not in one chunk as I have lots of other things to mix into my priorities like most of us.  I will spend some money on a trigger next and eventually get a Aero Precision upper and proceed.  Hey thanks all!