One thing people keep confusing is that an AR15 type 308 is NOT an AR 10. Armalite is an AR10 and the uppers aren't compatable, nor are the magazines. Armalite will ship some parts, but not barrels,or barreled uppers. I am going thru this right now. I have an AR10 rifle with a 24" match barrel and want to get a 16" upper to go with it. I can get an Armalite stripped upper no problem, but not the barrel. (Apparantly it is because all Armalite barrels are stamped 7.62 and they have no plans to change that) I don't know if thats true, Armalite didn't consult me for some reason. BUT a dpms barrel is supposed to fit an Armalite upper PROVIDED you use a dpms bolt carrier too. Supposedly the bolts are a few thou differant and could cause headspace issues. This is the way I am planning to go. You can also get a Krieger AR10 barrel which they say is no problem, because they are un chambered.