Ok so for home defense only, inside the house, short ranges, which would be the better choice? a 9mm carbine such as the Beretta CX4 or just stick with the trusty old Colt 6920? Assume both are equipped the same with, with a red dot, light, and 30 round mags. The 223 prob gets the nod for effectiveness? but would the low recoil/low flash of 9mm make up for the difference?