I've said it before and I will say it again. If you use the right bullet along with proper shot placement in the 243 it will kill a deer period. If you dont kill it, then it is the shooter and not the cartridge.

From some of the shooters I've been around. I would say a lot of it is the shooters.

Buy a .2506

On a recent Rusa Deer (size of a red hind) cull we used a 6.5x57 and a 223. With the 223 we used 53grn Barns Xs. on the shot in the arm pit the animals would not show much sign of a hit as the bullet only goes through light rib and lung but then only moves a few meters, sits down and dies while the herd mill around (a common result with many species).
We considered 60grn Partitions but found no reason to as the x's do the job, plus if a big Boar happens along the x's are great for their bulk.
I would think this should be the same with a 243, but then I haven't had a problem with old 100grn Norma ammo in the 243 I used and in fact found this set ideal for Wid Pig and Chamois.