I am a fan of the 243 also but I hand load 85gr.HPBT sierra game king bullets pushed by IMR 4350 powder and if I could only have one rifle it would be my Remington 700 in 243. It is a great rifle on coyotes, crows, chucks, coons, possums, deer and even a bear.

My brothers is a Winchester Model 70 in 243, My dads was a Ruger 77 tang safety in 243 and one of my hunting partners it is a Savage in 243. That is how well our family likes the 243.

My brother in Law bought a Remington Model 7 in 260. Great light recoil round and sure to clean your pockets of every thing including lint when buying ammo ARL today.

Another hunting partner has a 25-06. Does a great job and barks loud enough to let the whole world you fired it. I hunt a blind a mile and a half from his and I know when he shoots and wait for him to call for help dragging the deer across the cranberry bog.

Go with the 243 in about any rifle that you can get to fit your son. He will love it and may even come to like it so well he will not want any thing else. And as a gift from you it will be even more special.
I still have the deer rifle my dad bought for me in 1964 a model 94 30-30 It holds so many memorys I could write a short story about the hunts we went on together.

Al