I got 37 long guns (rifles & shotguns) My favorite that I hunt big game with our as follows. Out west, antelope = 25-06, mule deer = 7mm rem mag, elk = 300 win. mag. Local (Oklahoma, Texas & Kanas) whitetails & hogs 308 win & 7mm-08 rem. If I had to choose just one to cover everything? It would be 7mm rem mag. As far as brand, go shoulder several at a gun show or sports stores & see what is comfortable. Ammunition, I'd look at midway usa, nosler custom ammo in accubond or partition is hard to beat. Barnes also has good factory ammo.