The Magnum Research BFR 45-70 revolver is a special case. You really want to fire that one with one hand and let it roll upward. A two-handed grip can literally smack you on the forehead with that single action revolver. The barrel on my BFR is 10 inches. The cylinder is 2 inches to accomodate the 500 gr bullets.
To me, that size weapon is a crew served weapon only. My duties of the crew are restricted to observing for safety rule violations. That is not something I would ever tackle on my own!
I love watching guys and gals shoot .50 BMG's. My bonecracker keeps prodding me to try one, the sadistical, money hungry bugger that he is.