I never have hunted Elk with a .30-30 Win, I hunted a couple of times with a friend who would push deep dense revive(s) for Elk using a Win 94 in .30 WCF in the Cascade Mountains, he had killed a couple that way over the years, and from him and others who hunted with him told me he never lost one, My friend said; his shots were always well within the .30-30 range being quite close. I also have some Canadian friends who have hunted Moose with a .30-30 Win in B.C. Canada. Now this goes back to the late 60s and 70s hunting days. With that said; one of my favorite rifles is my (1942) Win .30 WCF I've never used it for Elk but if I had to I think it would work within its range limitations. I had another hunting buddy that used a Remington Mod 8 in .30 Rem for everything, it's pretty much the ballistical twin of the .30-30 Win. Don't get me wrong I don't think a .30-30 WIn is a good choice for Elk, especially big Elk... but yes, it could and has worked.
Just my 0.2 Cheers.