I'm new to this topic as well, but I'll tell you what I've decided on for a long range rig. After crunching a lot of numbers on ballistics programs, it can arguably be said that the 7mm Remington Ultra Mag is the flattest shooting cartridge for hunting purposes. It's close contender the 7mm Shooting Times Westerner is slightly behind, but we're splitting hairs comparing them. My reasoning for going with the 7mm RUM is because it supposedly is more accurate because it headspaces on the shoulder instead of the belt like the 7mm STW does. I'm looking at getting a Remington Sendero 700 in this and tinkering with it. A custom job would probably be the best but financially this is probably the next best thing for me. The best advice I can give you with this, as any firearm purchase, is to research extensively your choices. Talk with other shooters, gunsmiths, dealers, and of course these forums. Once you sift through all the data, the choice will be clearer. Good luck!