Hi Dave

Recoil -- there is a LOT to it. Without actually firing the gun, your son may or may not be able to handle it. Weight, stock design and length of pull, bullet choice are all factors. And as I mentioned earlier MV can be very critical. I can let you shoot 2 rifles of exact same calculated recoil and bet you'll swear one kicks almost twice as much as the other.

But there is nothing wrong with the 243. But don't buy muzzle energy either. That 55 is suited to varmints. Regardless its power. AND it could almost seem to kick as much as an 80 grain round. The rounds suited for deer are going to weigh 90 grains or more. Use the 55 and you may be very sorry and result in a wounded deer and upset son.

Be careful and you'll be just fine.

Jeff