Why do you need "2000 ftlbs at 600 yrds"?

You say you want a factory gun but you also want it to be heavy, factory guns dont come heavy.

Since you want a factory gun you are limited to a 30 cal with 220gr bullets (240s will require a faster twist) or a 338 cal with 250gr bullets (300s will require a faster twist).

I would suggest a 700 sendero in 300winmag with 220gr Sierra Matchkings with a 4.5-14*50mm Leupold LR scope. Definatly get a bipod, and I wouldnt worry about getting sloped bases if your only shooting 600 yards.