A .270 Win., .280 Remington, or a .30/'06 will be fine for hunting big game, (deer and everything except Alaskan Brown bears and Polar bears). With the right bullets, these three cartridges will do for those too, if you are a good shot AND KNOW YOUR QUARRY'S ANATOMY..... Now for turkey - I don't know where you live, so I have no idea if you can hunt turkey with rifles in your state. I used to hunt them with a rifle in New Mexico, but every place I have lived since then permitted shotguns only for turkey. Generally speaking, a 20-ga. shotgun is OK for anything you can shoot with one, but I woulduse a 12-ga. for turkey and goose hunting because the 12 will throw more shot.