KBintheSLC
Member
Some calibers are well diversified and deserving of more than one delivery system. I have several different .22's (pistols and rifles). I think a shotgun's performance can vary greatly between one with an 18" barrel with no choke, and a 26" barrel with full choke. 9mm works great in my Glock 26 yet is equally capable in a sub-machine gun or compact semi-auto carbine. Some rounds just seem to have more capabilities than a single weapon platform can perform on its own.