Well long storie befor the supressor came just after i orderd it,barrel is factory tight but not free floated. I sight in off my sled and 200 yds im in a 2" group with thermal, than go out and humt off tripod and shoot and miss a yote high, go back to sled and every shot hits 4"high so drop my sights re zero and go hunt! Mext yote shooting off sticks i shoot and miss 4" low. Go back to sled every shot 30+ stacks tight 4"low. It goes back and forth when i resight in. Once something shifts it stays, tryed 3 different thermals and bases now going to try a glass scope. Thats why i. Thinking of getting a different cal or upper. The gun was spot on the first 2 years and now when it moves it stays not like a flex or anything same amount up and down every time i go from sighting in to hunting off tripod, gun has a rail mount just after the mag. Sight in, hunt 4" high, resight in hunt shoot 4" low, resight in hunt 4" high it patterens great just shifts than stays there untill i re zero