.243 Win.:
Deer size game = [:@]
Varmints =

I've had/used a couple of rifles in .243Win. over the years, including when I was living and hunting in Wyoming. I found it to be a great varmint cartridge - for everything from
prairie dogs, rockchucks, on up to coyote. Much better than any of the .22 centerfires when the breezes were blowing. Used the Fed. Prem. load with the 85gr. BTHP bullet, or
handloaded it (Sierra bullet).
As for use on deer and antelope, not so hot. Oh, I got my deer alright, but I recall one
that took four hits thru the lungs before he went down, and he was just a spike. And yes, they were all good hits, just behind the shoulder. Not one made it out the other side. Each bullet came apart in the lungs - core/jacket separation. Range approx. 75yds.
Another small mule deer, taken with an off-hand shot at about 125yds, was shot as it faced me. The shot placement was perfect. Deer went down, but as I approaced, at about 15yds. this guy jumps up to run. I thought he was down, and made the mistake of having my rilfe slung over onto my shoulder. I drew my .41Mag. (S&W Mod.57, 4"), and put four quick rounds into his shoulder/lungs. Finally, he went down for keeps. Found the jacket for the .243 in the lungs, but never recovered the core.

Used the .243 on several antelope. Most went down ok, no problem. Most were shot within 150yds. But ,I recall one that took off when hit, and ran approx. 1/4mile. Fortunately, it was open area (as usual), and he took off with the herd at the shot, but dropped out after a few hundred yards.

I know a lot of other hunters who used the .243 as well. In many cases, no problems.
But, I've either seen or heard of too many cases of core/jacket separation. Too many cases failing to give full penetration, and poor blood trails. In no case would I ever want to use the .243 on bear. If I had to use it on deer again, I'd be sure to only use the newer premium loads like the Federal with the Nosler partition bullet, or maybe the Remington Core-Lokt Ultra, 100gr.

My personal minimum for big game hunting now is 270Win. You can almost never be "overgunned". Always better to have a little too much, than not enough. We owe it to the game to make as clean/quick a kill as possible. And, I'm getting too dang old to want to run around the woods all day trailing a well hit deer - hit with too small a bullet,
and poor blood trails to boot. I now use the .270Win. for "open" areas, and my Ruger
carbine, .358Win. for use in more thickly wooded areas. That .358Win. really knocks 'em down - quickly too.