well shooting distances of rifles depends alot on how often you practice with the gun at that distance. If you practice taking 200 yrd shots with your 30-30 and feel you can put a KILLING shot in the vitals go ahead. But practice practice practice!! As far as the moose thing goes, i dunno Ive never shot a moose, but Im betting you could take one down if the right bullet is used. Bullet selection, is far more important then caliber size.