have taken a lot of deer with a 243 up to 300 yds,shot a buck years ago in the throat at 287 yds,using a hornady 87 gr bullet.Lucky----maybe??
Don' t use it or my 06 much any more because I have a lot of other calibers,I usually carry a different gun every time I go,because I like them all.Have a new 280 and 270 wsm to try this comming year till I take one with them.To me a 243 will make them just as dead as anything else.
With any caliber you need to practice more than the day before season opens.
Good luck whatever you choose.