I have a 1-8 twist Ruger American .22-250, and used it 2-3 years ago to kill the largest pronghorn buck in the area, at 350 yards. The bullet chosen was the 70-grain Hornady GMX, though I tried some others in the rifle, including the 62 TTSX. (The 70-grain AccuBond was not quite available then.). The Hornady shot the best, so got picked. It worked fine, penetrating to the far shoulder on an angling away shot, and retaining all its weight.
I knew it would work, having experience with .22 centerfires on big game going back to the late 1980s when my wife was using a .220 Swift with 60-grain Nosler Solid Bases, the soft-point forerunner of the Ballistic Tip. As far as I could tell, it worked just about identically to the .243 Winchester on antelope and deer, except for shooting flatter at "normal" ranges, due to a muzzle velocity of 3650 fps. And we never recovered one, if that makes any difference. They left an exit hole about like a 100-grain .243 bullet as well.
Also have a local friend, a retired outfitter, who's been using the .22-250 on elk for a number of years now. He only hunts cows anymore, and when he gets up on a herd, he put whatever 55-grain he's handloaded behind the shoulder, and the cow falls over pretty quickly. He much prefers the .22-250 to the 7mm Remington Magnum he used during his outfitting days, because it kicks less--and the bullet never exits, preventing hitting another elk in the herd.
Before anybody gets excited about this possibly being illegal, Montana has no restrictions on what caliber or case length or bullet weight or WHATEVER you choose to use on big game. You can hunt them legally with a .22 Long Rifle, but apparently our game department takes the view that hunters will use something that works, even if in somebody else's imagination it won't.
