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.