So, I went out to the range and shot my match target earlier, then plinked around for a bit after.
It seems that someone had picked up a bunch of fired .356 copper jacketed bullets and left them on the bench.
Looking at them, I thought to myself " hmmmm I wonder"...
I was thinking about how ingenuity and adaptation ruled in times of hardship and scarcity, and wondered how they would shoot in my .45 flintlock.
I fired 3 shots with 40 grains of fffg, and the bullets loaded pointy end forward wrapped in 3 patches to make up the difference in bore size.
Accuracy was awful, with keyholing, and about a 14" group at 25 yards, as you can see in the picture with yellow circles.
Then I wondered what would happen if I loaded them pointy end down.
I was amazed!! I put 4 shots in about a 3" group at 25 yards, and they made fairly round holes with no keyholing.
If you used a bullet closer to bore size, you could probably get even better accuracy.
It's certainly sufficient accuracy to put meat on the table, or defend yourself in a survival situation.
I want to try to up the charge and see what it can do at 50 next time.