+1 on the 6X47/6X222Mag !

Some states have caliber restriction along with energy restriction that the Whisper may not meet.

When my children started competing and shooting deer at 6 yrs to 10yrs this is the caliber I built for them to learn on. No more recoil than a 223 with the lighter bullets. Not much more with an 80 grain. Legal and efficient killer. My wife bagged her first few deer with it as well.

Put a forward venting brake on whatever caliber you wish and many including your 243 won't have any recoil.

Neal