[jimb1972]

.300 mag is a great round, but you will burn a lot more powder than in a .308 and brass/ammo is not as common as .308. .308 is used by the military most frequently and good past 600 meters. I am a fan of the lowly Marlin model 60 in .22lr, you can find a good used one for $100 and they are very common so parts are easy to find.