My Remington R-25 308 was made by DPMS. It takes the cheaper 308 Pmags, DPMS or C-Products mags. The forend is free float and came with the Remmy camo dip.
I installed a Timney trigger, GG&G BUIS, a BCM charging handle and had Kreiger put a 20" M110 barrel on it with an Obermeyer chamber.
It's heavy...To me that's a "Who cares". I'm not lugging it around the mountains of Assholistan.
And that weight means there is so little recoil that I can spot my own bullet strikes.
It shoots REALLY, REALLY freaking well and currently wears a Zeiss Conquest 3.5x10x44.
That may be changed to the Zeiss 4.5x14x44 I have if I ever get a roundtuit and put the 3.5x10 on my 20" hunting AR upper.
Having never owned or shot an Armalite AR10, I can't help you there but I know there are a lot of aftermarket parts available for the DPMS platform.