I am looking at a light weight mountain rifle in 7mm. For use on Elk size game. The 7x64 cartridge and 280 Remington are two candidates that interest me in a light rifle. Has anyone any experience with the 7x64. It seems that the factory loads and reloading manuals load this cartridge way below its true potential. Why? Good quality brass is available from Norma. If you had the choice between the two which would you choose? or should I pick another cartridge?