I just finished building my first ar which was a dedcated .22 and am planning on my 2nd with the usual 223 5.56 set up. I am looking for home defense, perimeter defense. If shtf maybe hunting, or should I not compromise this gun. I am looking at BCM Standard 16" Mid Length Upper Receiver Group w/ YHM 12" Handguard. Any upgrade suggestions at this point? Lighter barrel, shorter barrel? Twist rate 1:7 is what this is but is 1;8 a better choice? Also I heard that the setup should be chambered for 5.56 as you can shoot 223 if you want with a bit less accuracy but if its the other way around it isn't good. I assume the BCM is chambered for 5.56?