Love the 204 Ruger as a walking around varmint and predator rifle. I am in a cougar rich environment and would love to take one of these predators down. Are there any new 20 cal bullets out there more suitable to the slightly larger predator? My dad used to shoot lions with a 222 out to 200 yards and said they're not as tough as people think and the 204 should work. Bullet recomendations please...