hello there, i have a .223 that i just started shooting. if i decided to keep this gun and shoot it for coyotes, prarie dogs etc out to about 400 what bullet would be best? right now i shoot black hills 60 gr Vmax... i would like to stay with black hills and will probably not reload for this gun. for the above mentions quary, should i step up to a 77 grain match king, or down to a 50 grain vmax? any other factory rounds to look at? thanks!