A few months ago I zeroed a friend’s Sig 716 with a Nikon 4X12X40 scope. The 716 is an AR10 that is exactly like an AR15 except it is chambered in 308. The 716 is a gas piston operated rifle and is very easy to clean. It is very accurate at 200 yards and the scope is a $200-250 bargain and performs quite well. The only negative for me is the trigger and it really is not that bad. I prefer bolt action models in the 308 cartridge. I have a Sig AR15 and will review it in the future. I posted a five minute video on the 716.