Yes... no minie balls that I know of during the American War of Independence, but... I got a new mold, so why not experiment.
I recently picked up a 54 cal Lyman mold for a 425gr Minie Ball (#542622). The rifle is a 54 cal Pedersoli Jaeger flintlock rifle. Barrel twist is 1 in 24”. It’s actually a very good representation of a basic, unadorned military Jaeger type rifle that would have been carried by Hessian or German troops in the late 18th or early 19th century. BTW, despite being a fast twist, this rifle shoots patched RB very well with my standard 90gr FFg load. Doesn’t make sense, but it works...
Minie balls work with a 19th century rifled musket, so why not a flintlock? I cast up the minies and lubed them with my 50/50 beeswax and olive oil mix. As dropped they miked .542. Too large to load in my rifle. So I had Lee make me a .535 sizing die and resized them. They loaded just fine. First three shots with 80gr and the cavity filled with lube resulted with no accuracy and keyholing. The skirt on this minie is very thick. I removed the lube in the cavity and upped the charge to 90gr FFg and was rewarded with a ragged hole.
I was able to load and shoot as much as I wanted without wiping the bore and having any resistance in loading. Completely unlike a patched RB. It made for a very easy range session.
Experiment was successful.