I'm looking for guidance and info because I'm a newbie to the ar world. I'm debating a 10.3 or a 11.5 for my sbr build. I've read a little and a lot of people say 11.5 for smooth operation. I might silence this down the road. max range I might shoot with this for a grin only is 200-300 yards. Mostly be for a home defense tactical training classes if I'm allowed to bring a sbr to one. And fun/plinking. Enlightened me. Or if you know some good threads to read that will work to.