Did you have to trade a kit for that box of 300 blkout?
Technically you only need one arm to fire an AR pistol.
Seriuously though, .300BLK has never been really cheap to shoot, and prices are starting to come down some. Also, I really wanted to get my subsonic setup dialed in with my can as I wasn't really happy with it. So as the old saying goes; "You gotta pay to play."