RE: Best caliber for under 100 yards ?
personally i like the 45-70 for shorter range work. and if you want you can get in in a lever action again, or single shot for that matter. also a lever action in .44mag, .45colt, or the ruger deerfield semi auto carbine in .44mag.
if you are looking for a bolt action the, 7mm-08 or the .243win are good choices. i also like the .308 due to cheap military surplus ammo that can be used for plinking at an affordable price
propmahn
you can never have too many guns