The Socom16 does have some peculiarities. The muzzle brake/gas cylinder lock is proprietary. You need things like a DeltaP adaptor or a SEI Socom16 gas lock if you want to run a can or other muzzle devices. SAI Socom16s have a small issue in the muzzle brake, there is a small gap between the muzzle and the rear interior face of the brake. This causes exiting gases to not flow evenly disturbing the bullets flight. This is a cause of the Socoms16 reputation of not being accurate. Tighten the gap and accuracy improves, couple of different way to do this.
Also, some do not like the scout rail and remove it, this can also change how your gun shoots. Some feel the factory rail isn't stout enough for a glass optic, the Ultimak is considered superior. I run a SIG Romeo5 red dot and it works fine, no heat issues so far. The front sight is fat and the rear aperture huge, ok for 50 yards or so. Some like changing the rear to a standard USGI aperture.