I am currently in the market for a good 300BLK upper to pair with my Ruger AR556 lower. I haven't been able to find an answer to the question of what length gas system to use for a 16" barrel. Pistol length or Carbine length? I doubt if I will be using subsonic rounds or purchasing a suppressor anytime soon and it will be used for hog hunting and deer mostly. Thanks for any replies!