Based on my experience, a bolt-action upper is a smart move for accuracy. It gets rid of all the gas system hassle, giving you a clean, reliable shot. I tell you, it's a game-changer
I got a suppressor not long ago, and it’s probably worth getting a bolt action upper just for that. Semiautomatics with suppressors blowback gas through the gun, dirtying it up, and you breathe the gas too. Some are worse than others
I picked up a suppressor and built a bolt action upper for it. I noticed way less blowback and the action stayed clean between strings. Semiautos with DI systems pushed gas into the receiver and my face felt it more..so now, for quiet, clean shooting and better longevity, bolt actions won for me