So - how's it shooting? To early yet?

In re-reading this entire thread, I'd only go with the patched,undersized balls if full sized balls didn't regulate well &more experimenting is needed.

I'd also try some harder alloys than pure,like WW or a WW/pure mix, due to the pure lead's propensity for obturating when fired in cfg. guns. Seems more so than when in muzzleloading guns. If completely pure, they will forshorten and enlarge in diameter. I'm of the stong opinion that a perfectly spherical ball will be more accurate from a smoothbore, than a virtually flat ended cylinder that is shorter than it's dieameter.

The harder, bore sized balls might be more accurate, but a patched ball leaves lube that softens fouling preventing it from adhering to the bores. Lubed wads can help with bore sized balls.

What a beast - 273.5gr. of powder - eyowch!

Good luck.