On the original topic, I just wanted to say that...if you are looking for a firearm for yourself and your son to shoot, it might be a good idea to look into firearms labeled as, youth size. Youth sized firearms have a shorter length of pull, which is basically the length of the stock.

When firearms are designed, they're typically designed with the average size man in mind. Women and children are of a smaller stature on average and therefore typically need a shorter length of pull to shoot a firearm comfortably and properly. Otherwise, shooting a firearm with too long of pull can be extremely uncomfortable and often quite unsafe.

This is one of the reasons why adjustable stocks have become so popular on modern firearms, as they can fit a wide range of shooters. Though, I don't know what the legalities of adjustable stocks are your location.