If I were you, I'd try to meet up with someone that has several rifles that would be willing to let you take a few shots. If you're planning on sticking with something pretty common, you'll be fine with .308win or 5.56/.223. There are plenty of very good rifles for either caliber.
As for those saying to get a Mosin Nagant, I haven't gotten one yet but will simply because they're really cheap. I will, however, still prefer my Mausers. And please, stop saying the Mosins have some stout recoil, my 7 year old nephew could handle the recoil with no problem.
Does he by chance have a 5 year old sister, with a pistol colection in her closet.