I don't have a flint handgun, however years ago I and anyone willing to try used to shoot (just for hoots) a CVA Hawkins 50 cal pistol using 50 grns of fffg and a pillow ticking spit patch with a .490 round ball and #11 CCI caps. At the IHMSA range it would seemingly knock over the pigs a chickens with as much authority as my light loaded 44 mag. With a decent cal. and reasonable ranges I say give it a whirl. Don't forget to let us know how it went.