Cal, unless you're getting something special, factory loads are pretty mild because of the liability factor of not blowing up trapdoor rifles. The loads I made up for my Marlins (both the Cowboy and the Guide Gun) are pretty stout because I use them for bear hunting. I've taken 3 with the Guide Gun and 300 gr bullets. Now I want to carry the Cowboy with the 405s cast bullets and see how they perform. I know penetration won't be an issue but I'm concerned a bit about expansion.
BYW - about the LOP - I did punch myself in the nose with my thumb a time or two with it.. lol