i love my .243....with 105 bthp out to 500ish, it's an amazing shooter.

actually using hunting bullet 100 gr spbt, the point of impact and group size is just slightly bigger than the bthp, plus a little more economical to shoot - plus if using the rifle for dual purpose target / hunting using those spbt keeps the same dope.

i used the amaxes, no real substantial gains over either of the above (unless of course you are going benchrest shooting where a 1/8" is huge) until after 500Y.

I'm using H-1000 powder which burns a bit slower and is easier on the throat erosion AKA barrel burning. of course that reduces the full potential out of my .243 by a few hundred FPS, but with the groups i'm getting (3.75" at 425Y) i don't mind adjusting the elevation knob a few more clicks.

i really wish i'd have gone with the .243 years ago, i just started with it about 4 years ago and haven't been nothing than tickled to death with it. very adaptable to plenty of applications, even with off the shelf ammo. if your reloading, it get even better.

the only other short action caliber i'd consider from here on out would be .260 rem or 6.5 Creedmoore