You CAN hunt whitetails with a rifle cartridge in a rifle. It's got to be a special cartridge tho! .358 or larger dia bullet AND max brass length is 1.62" (I'll bet you knew that already!
The first one that comes to mind is a .25 WSSM necked up to .358 and shortened .020" just to ensure it's legal.....
I know it would be a LOT of work, but a .408 Chey-Tac shortened and necked to .375 or .358 would work even better!!!!!