Fact is that DPMS, Sig, Remington, etc, are all good in the 7.62 caliber. The problem with Armalite is that they use proprietary mags. You can't just use any 308 mag.
Yep, the SIG 716 is bad a$$... and it is light for a 762, lighter than some ARs in 556 out there. Pricey, though.