back in the late 70's I had a Gallagher Breechloading Carbine. I got the Lee Improved Minie mold for it. Cast up a load of minies, and discovered the Gallagher liked RB's better.
Fast forward to just a few years ago while I was searching the garage for something else - I found the Lee minie mold & a large jar of already cast minies, plus a 30 year old can of Pyrodex.
The minies look as new, and the pyrodex worked like new, too, despite over 25 years storage in a 160º summertime temp garage shop.
With roundballs in my .54cal Flint Deerstalker, Flint Trade Rifle, and cap Cabelsa "Sporter" Hawken, I can plink grapefruit-sized targets all day long. At around 50 yards the RB & Minie perform with nearly same POA (maybe /25" lower for the Minie.
At 100 yards, the Minie drops off 3-4" and groups poorly.
I seldom use the Lee minies, except when plinking gallon water jugs at 50 yards or less.
That 40+ year old jar of minies may last me another 40 years :rotf:
If I took time & effort, I suppose I could work up a heavier load for the Lee Minies to get better performance, but they would be no fun to shoot because of excessive recoil. Plus it's a waste of the extra powder needed to make them work beyond 50-75 yards. Also, the Minie wastes more lead per shot & from elk to barking squirrels, won't kill any deader than the capable PRB already can.