I have over 40 years of elk hunts under my belt. I have shot and/or seen elk shot with the following;

243, 25-06, 6.5 Swede, 257 Roberts, 257 Weatherby, 270 Winchester, 270 Short mag, 270 Weatherby, 7mm Mauser, 7-08 7MM Mag, 280, 308, 30-30, 30-40 Krag, 30-06, 300 H&H, 300 Winn, 300 Weatherby, 308 Norma, 338-06 338 Win, 35-Whelen, 9.3X62, 375 H&H, 416 Taylor, 416 Rigby, 45-70, 458 Win,

50 cal muzzleloader with balls, 54 cal muzzleloader with balls 58 cal muzzleloader with balls and bullets both, and 62 cal muzzleloader with balls.

Also both wood arrows and aluminum and carbon fiber arrows.

Plus 44 magnum handguns and 454 Casull handgun.

and I have probably missed a few on this list.

What have I learned?

Every one of these kill elk just fine if the person using them uses them correctly, and if the bullets don't come apart too fast and impede penetration.

Guns don't kill elk.
Cartridges don't kill elk.
Even bullets don't actually kill elk.

Wounds kill elk!

If the wound is in the right place and deep enough, and if the wound channel is at least 1" in diameter, it kills just fine.

How it got there is not important to the elk.