I know they say 1000 ft-lbs for deer.

For elk ideal in my book probably starts with a .30-06 and goes up from there.

I think the .300win.mag is probably one of the most ideal.

.338win.mag, .340wby.mag,
7mm Rem.mag

270win starting to get a lil light IMO. esp if I have a .300mag to use, etc...