Under 200 yards, I've killed 250lb hogs and under with handguns and a 222Rem with 63g SMP's, but I prefer to use one of my 20" AR's in 5.56 and a 62g TBBC's or the Barnes. But, most any caliber deer round will work, but I do recommend a bullet that is more on the tougher side for good penetration. Larger boars, at least where I hunted, were on the tougher side and favored larger bores for quicker kills and less tracking. I have seen a very large, old boar stop a 30-30 on its heavy shoulder plate, but quickly succumbed to a 308 with a 165g.