Hey guys. I'm wanting to build an ar 10 and have some questions. I want to use a lower from a rock river arms or bushmaster if i can find one. Could i use an upper from another manufacturer, like dpms? Also what parts are interchangable from ar 15 to ar 10, if any. Thanks for the help.

Building an AR10 or .308 AR is a lot different than building any caliber weapon that uses an AR15 size lower. It's also more expensive. DPMS parts are compatible with Knight's Armament parts. AFAIK, Armalite AR10 parts are only compatible with the Armalite AR10. I'm not going to pretend to know more than that.



TS



to the Armory!

The Rock River and Bushmaster 308 ARs are the same or a very similar design. Bushmaster dropped the model RR picked it up. It is one of the least common 308 AR platforms. If you really want to build one it would be my last choice. Whole rifles are hard to come by, parts are almost impossible.

DPMS, CMMG, Knights, Fulton, POF and probably some others are based on the SR-25 magazine design and use mainly interchangeable parts. If I was building this is where I would go. I bought a DPMS LR-308B 21 months ago and am very happy with it. I started to build another from parts but discovered that even used parts were costing more than an assembled rifle so I sold my parts after Obama was elected.

Armalite uses its own magazine design which is a modified M14 magazine. Some Armalite parts can be exchanged with DPMS rifles, many can not.

Thats what I was afraid of. Thanks for the replies guys!

that's the route I was goin when I was workin on a .308 build, gave up that n now onto sumthin I think should be a lil more satisfying for me now that the parts mfg and ammo for it has opened up some

AR 15 parts thatwork on .308 platforms include the fire control groups, the standard pistol grips, safety/selectors, butt stock assemblies with different recoil springs and buffers.

My suggestion on picking a platform is to figure out what mags or upper you really want to use. Bushmaster/RRA use FAL mags. Knights, DPMS,POF, LaRue and several others use the original pattern AR-10/SR-25 mags.
Armalite today uses modified M14/M1A mags.

Now here's where it gets tricky. Uppers used by the manufacturers don't folow the magazine route. Knights, Armalite, LaRue use AR-10 pattern upper receivers. DPMS are unique. Gas tube lengths differ from DPMS and AR-10, as do barrel nut sizes and threads, as well as Bolt/bolt carrier design.

I decided to go with a DPMS pattern lower made by CMMG for best mag compatability (Mags to be made by Knights, LaRue, Mag-pul, C-products, DPMS). My upper will be one of DPMS A-3 types with FA and dust cover. Barrel will be a Krieger. Shot a rifle set-up like this that was scary accurate. His had a 24" barrel But I'm going with a 20".

This post has been edited by SSGN_Doc: November 7th 2009 1:36 PM

ok Doc sounds like you dug about as deep as I did on this one, question I couldn't figure though, would the POF uppers fit well on the CMMG G3 mag compatible lower?

I think the POF uppers are a DPMS cut, and the CMMG G-3 lowers are as well. My only problem with the G-3 lowers is the lack of a bolt catch. Cheap mags is hard to discount though.

already got the lack of a catch covered bud, makin holes is my specialty