You need to build three rifles....
1. 338 Lapua
2. 300 WSM
3. 7mm RM
Once you build these three you will have the best long range arsenal ever. Then please take photos and post the pictures since I can't afford any of those at the moment.
Go with the 7mm RM. Tons of bullet selections, tons of load data, can shoot 130 class bullets up to 180 (depending on twist), major rifle manufactures chamber their rifles in them, High BC pushing .530, and with a 150 grain bullet at 3100 FPS will be 29 inches low at 500 yards, and can harvest pretty much any north american game (with good shot placement).