AR 15 Ammo

[rich]

I have been doing some reading on ammo for the AR15 and was wondering if any one knows if there is much difference between the Black Hills 77 gr Sierra Match King in 223 and the military MK 262 Mod 0 or Mod 1.I read the military is loaded hotter and was also wondering if there is anyplace to purchase military brass to reload. I don't think there is any way to purches the military ammo. I have a colt M4 type carbine and a bushmaster of the same type with a 16" barrel 1 in 7 twist. Now I am shooting black hills 69 gr. Sierra Match King and was wondering if the heaver bullet would make a difference.

[aubie515]

With a 1:9 twist and wanting to shoot a 77gr bullet, you should be getting a 1:7 twist barrel.