Has anyone tried....

[Tuolumne Lawman]

In a .45 Colt Spencer, a 300 grain bullet with about 35 grains Triple 7???  Biggest problem would be the 300 grainers are semi-wadcutters.  It would have almost the same thump as the 56-50, but easier cases....

[Herbert]

You should allso get better acuracy with the longer bullet

[mtmarfield]

   Greetings!

   If you're looking for a heavier bullet, try the Lyman #457191; it's a vintage, light-weight design for Winchester Rifles, rated at 294gr. Dad tried them in his Ruger Black Hawk sized to .454"; he said that they shot well. I'd start easy on the powder charge; otherwise, I'd say that it would probably perform well.

            Be Well!

                         M.T.Marfield
                            3-18-12