RE: Best caliber for under 100 yards ?
Under a 100 they all work fine, I would just stick with ole faithful. Bullets are cheap, easy to find can go up or down.
If you just need something, then 308, 35 whelan, 3006, 7mm, 300 win, 300WSM, 270, 280, 7mm08, etc...get my drift it don't matter.