I know it's not historically correct, but I just had to try it. I've gotten so addicted to black powder that I have to try to stuff it into almost everything I own in the way of firearms. Having just purchased my first 1911 a couple of months ago, it was the next logical victim. Somewhat to my surprise (even after reading some other experienced folks comments here) I found that it seemed to be quite happy shooting Holy Black. I loaded 42 rounds, cause thats all the bullets I had cast up at the time and I didn't really expect it to run that long without fouling out. In reality, it digested all 42 with no malfunctions and appeared ready to eat quite a few more. I disassembled the gun and found the barrel and all internals "well lubed" and with very little residue in the barrel and chamber. After one dry patch, it was almost spotless.
I used DD's DD/PUK/ROA bullet with Pearl Lube II over 16.5 grains Goex FFFg. Now I can't wait for our clubs Wild Bunch match next month!