i see no problem with your choice but for the fact that what do you shoot most, reds fallow etc or roe, muntjac,
The .243 is effective on hill reds fact, if poor placement of the bullet is to blame then surely this is not the rifles fault but the shooters.
i've seen all deer species in ireland hit with .308, .270, 6.5x55, 6.5 x 284, all hit reds and the deer run, shooter error, not rifle.
If your a competent shot the .243 will be a good all rounder...............