I've killed lots of deer, both whitetail and mules, with the .243 Winchester. And, of course, I've bonked a fair number of antelope with it and the .243 WCF works wonderfully.
I've had occasion to kill two elk with the .243 Winchester and they simply tipped over quite dead at the shot. On both hunts, there was an excellent probability of deer, not a chance of an elk showing up, and I had both tags in my pocket.
So what's a guy to do when Mr. Elk shows up? I've always thought that the very finest rifle for the job is the one you have in your hand.
Anyway, I cannot say that I'd recommend the .243 Winchester for elk, but on the occasion that an elk shows up and I have a .243 in my hands, I'm gonna kill the bugger.
Soooo, my score on elk with the .243 is two shots and two kills. Similarly, my score on mule deer with the .223 Remington is three shots and three very dead very large mulie bucks.
I've also killed a number of elk with the .25-'06 and it simply kills elk BANG-FLOP dead. The 100-grain Hornady Interlocked is my favorite on elk, closely followed by the 100-grain Ballistic Tip. Place either of those wonderful little bullets tight behind the shoulder and an elk simply crashes to the ground.
Years ago, when I used to guide elk hunters in He11's Canyon, our cook used a .250 Savage on elk. She'd never actually go hunting, but sooner or later a cow would show up and drink from our horse's watering hole. I cannot tell yu how many elk Cookie killed with her Model 99, I can only relate that it was LOTS (over 15) and that she NEVER shot twice.
A couple of times, I came into camp and Cookie would tell me, "Steve, I've got a cow drug out of the pond and hog dressed. If you want a SPECIAL DINNER, please finish the dressing, skin the big bugger and hang the quarters."
"Yes, Ma'am. Peach Pie and all the trimmings are about to happen. Washed down with a couple of beers and I'm a happy, happy guy."
Steve Timm