RE: how many rounds can you put through a rifle?
The Army used to rate the useful accuracy life of a 1903 Springfield .30/'06 at 10,000 rounds. But with today's steels, it may very well be up to 20,000. It will last longer if you don't shoot a lot of ammo through it after it gets real hot - let it cool between shots, and it will last longer than you will!!
Keep yore powder dry!!