It sounds to me as though you are set on an AR type . If that is the case be sure to get the 24" barrel if you intend to shoot 500yds with
any regularity. If a 30/30 and muzzle loader are your experience base
you are in for a real awakening. Long-range shooting skill is a skill
that comes only with practice,practice,practice. If you don't reload
this will become an" expensive" pursuit also.
GOOD LUCK and GOOD SHOOTING!!!