When I was guiding elk hunters near Dubois, Wyoming (along time ago), we guides would fight over the clients who brought a .270. To a man, they could all shoot and weren't afraid of their gun. It ment less work for us.
Those hunters who showed up to camp with the newest an latest cannon were left to the guide who drew the short straw. Nearly all of them couldn't hit what they were shooting at because they were afraid of their gun. And besides, the guys with the really big guns usually had the really big egos.