i have been hunting with a 243 for many years now and although most of the hunting with this rifle is varmint and predator i have shot a dozen or so nuissence(legal permits)deer with this rifle.have never had a problem with lost deer.but i will admit that shot placement is critacal.but then again it should be with any caliber.my personal feeling is if deer size game is your spacific target then your time would be better spent carrying the 270. but the 243 with 100 grainers will do a fine job.