also if you are looking for an upper for home defense, against elephants, this one shoots lethal high velocity golf balls, just an option to keep in mind..
haha. 45/70 ballistics in a semi auto.. and as much ammo capacity as a single stack .45.
If I were to venture beyond 5.56 for home defense, I'd stick with 300blk and go with subsonic rounds. Low recoil, slightly less noise to keep your hearing intact. Adrenaline doesn't always attenuate those 170dB muzzle blasts..