I have killed several whitetail deer with a Ruger No1 in 243. My wife used this same rifle to kill several whitetail, antelope and a Rem Mod 7, 243 to kill several whitetails and a couple of very big bodied Colorado mule deer. We always used either a 100 gr Sierra or a 95 gr Nosler Partition.

Never had any problems.

Not a .243 guy here but I've had success with an old Remington in 6mm. Handloaded with 100gr. NP's it would strike 'em dead everytime. I think the owner has since moved to the TSX and BT bullet styles but the 6mm still brings home the venison.

I know another who swears by an old stash of Core-Lokt .243 ammo for his old Remington, and it also gets the game.

My preference would start at .257 and go up, but everyone has different experiences which lead to different opinions, so the real answer is ignore all of us and do what you think is right!

I agree that we all have different experiences. I for one after seeing the damage done by bullets that work well in the 6MM's can't fathom why anyone would say they are not enough gun. On the other hand I haven't made a truly bad shot on a deer with any rifle in 30 years so that may jade my thinking.