I have that very rifle and like it well enough. Very accurate and attractive. Depending on how big your son is, he may find the CZ Euro-stock a bit of a challenge. I'm six feet tall and find the length of pull just right but many people feel it's a bit long. There is also a ton of drop which is fine if, like me, you have a meaty face and don't crawl the stock. But your boy might find it distracting. The 550FS also ends up being a bit heavy when scoped. CZ uses a heavy barrel profile to avoid the wandering zero that can sometimes afflict Mannlicher-style rifles. Couple that with eight or ten inches of extra hardwood and the overall package is heavier than it should be.
Despite the negative tone of the following paragraph, I like my FS. As I said, it's scary accurate and despite the weight is a very handy, very well-balanced package that points well and quickly for me. Don't sweat the short barrel. In the first place, the Swede does not need velocity to work. In the second place, CZ actions are stout and you should be able to make up for that shorter barrel with judicious handloading. Finally, my rifle proved to be just as fast as a Kimber M96 sporter (22 inch bbl) I used to own proving that velocity differences depend more on individual barrels than they do on pure barrel length.
