Sorry to disagree with the rest of the Wolf clan, but I would want my son to learn the basics first. I would want him to shoot Pyrodex RS or even black powder. And with moderate projectiles the recoil would be light. Since recoil is a factor, I would look at some of the youth model rifles or a traditional rifle. All too often the traditional rifles are over looked.

If your determined for an inline the Wolf would be considered, but I would also look at a Knight Wolverine Youth model. While it is older technology, it would be hard to find a better shooting more dependable rifle for your son.

If traditional is your thing, look for a Traditions .50 caliber Woodsman Hawkins. They are not a heavy rifle or overly large rifle, but because of the excellent stock they soak up recoil beautiful. Loaded for roundball, it would be a perfect 75 yards and under rifle that your son could learn on and treasure all his life.Because of the 1-48 twist, mine will also shoot powerbelts and can be loaded up to stronger charges, as your son gets bigger.

There will always be inline rifles out there. Traditional rifles will become harder to find I believe. Plus a traditional rifle will really works a young man's imagination and desire to shoot and hunt.