I've been interested in getting into target shooting, however I am confused with all the different calibers for this application. Not trying to phrase this as what is the best cartridge. I would like to know the benefits of different calibers of the 6mmBr, 6PPC, 6.5x55, 6.5x285, 6.5x47, 6.8SPC, and others. Most likely I would be using these at 100-600 yards. Also it seems very expensive to shoot these rounds for the price I could be using a 300 win mag. Any info on what you use or benefits of the differend calibers would be greatly appreciated.