I really like my 243's and have killed a fair share of white tails with them. I also like the 7MM 08 and have killed a few white tails with them also. I would really buy a Remington Model 7 in 260 for my son if he were 9 again. A bit beefer in bullet weights can be had than with the 243 and can handle many of the same bullet weights as the 7mm 08. The recoil is an in between thing. Might add a tiny bit of weight in the stock to help with the recoil also. If you have the bucks Mag in port it andf it will feel like a 22LR.
Al