Thanks guys. Poor_Man assuming your barrel is 1in7". According to DocGKR from Tactical Forums, the lowest velocity for 75 gr Hornady and 77 gr Nosler still fragment decently is 2100 fps. From a 14.5" barrel, a Mk262 MV is about 2500+, you are probably good for 100+yds before the bullet velocity hit below 2100 fps. I don't know about factory grade and surplus rounds, since my research was concentrated on 75gr handload. I say stick with the Hornady 75gr 223 TAP or BlackHills and try not to engage BG over 150yds.