Minie Balls for Lyman Great Plains Pistol?

[Mike Goldstein]

What do you all think about using these:
 
Lee 1-Cavity Improved Minie Ball Bullet Mold 500-360M 500 Diameter 360 Grain
 
Lee 1-Cavity Improved Minie Ball Bullet Mold 540-415M 540 Diameter 415 Grain
 
for use in the .50 and .54 cal Lyman Great Plains Pistols?
 
Also, if I use a Minie Ball, could I use an alloy that is harder than pure lead, as I should not have a problem ramming them home?
 
Thanks,
 
Mike Goldstein

[Shorty]

Mike,
First off, a minie ball has to be dead soft, even more so than a round ball.  The skirt must be able to "blow out" into the rifleing to function.  
Also, a Minie works best with wide, shallow rifleling and your pistol probably has narrow, deep rifleing.  Still, I wouldn't say that you can't make it work.  Part of the function of a Minie is that it flies like a dart or an arrow, with the weight-forward to keep it straight.  Getting rotation just stabilizes it.