[john kilgore]

Smokey Joe's advice is generally correct !
However, there are circumstances where you use what is legal, or don't hunt.

In Ga., on most of the State WMA's hogs can only be hunted in "small game" seasons with small game weapons. The favored round is the .22mag.. My own experience is that it performs poorly even with well placed shots. I shot three this past season in head and all three ran off (150-250lb). Also killed two with one shot - But-, they weighed 10 and 8lbs respectively. Size of game animal dictates gun. I now use a .50cal muzzle loader w/370gr Maxi-ball for hog hunting.
It's legal for squirrels !!! At this time, a .17 HRM isn't.
Go figure !!!!

.22cf w/55gr bullets or heavier do well on deer even with marginal hits. I've had better results w/.22cf's (.223, 22-250)than any .30cal- .30/30 equivalent or less. I've never lost a deer with a .22cf, though one I shot w/50gr Rem PHP took several hits to stop. Even a .22 Hornet gives better performance than a .30/30 with 170gr or heavier bullets, (at least in my personal experience). Most of deer I've shot in past 12yrs are with Hornet, 30 plus at this point. Last deer I lost was last year with .35 Rem. w/200gr cor-lokt @ 2,250fps-mv, at 125yds with a chest shot. Trailed blood for 250yds before blood played out. Deer carcass was never found, even by the buzzards.

However that all said, you can't go wrong with the .30/06 and 165gr bullets on any thing less than 1,000lbs.- As long as the bullets are well constructed.

For What its worth......................
Today in Africa, most elephant are killed with 7.62x51 Nato, or 7.62x54R Russian from automatic battle rifles (FN-FAL, or Russian "RPK"?) in "cropping" operations. A 147gr. FMJ well placed, does the job; if not, then the rest of the 20rd magazine in 2-3 seconds.
"Sho-nuff gun!"