If you are really serious about long range (2,000+ yds) accuracy then you should consider the 416 barrett and the 408 cheytac. both are exceptional. The 50 isn't as accurate on cold bore shots.
Also, you may know this, but when you hit about the mile mark, things begin to get really, really expensive. Heck, a rangefinder is at least $6k to get you that far... and that's just to start!!!
Let me know if you have questions or need help...
John