Here's what Wallace Gusler (Head of Conservation & Master Gunsmith @ Colonial Williamsburg) & Gary Brumfield (another Master Gunsmith now occupying a dangerous clerical position @ Colonial Williamsburg) told us: Our early Colonial forefathers carried only one horn and used only one type of powder. The same powder that supplied the charge for the barrel was used to prime the pan. Even soldiers on both sides of the French-Indian War and the American Revolution used only one grade of powder. If you have any doubts, read Francis Parkman's book, Pontiac's Conspiracy. In it he tells of the Siege of Wheeling (now in WV) where a "squaw" ran from the blockhouse to retrieve powder in her apron. Intiially the Indians didn't shoot at her when she ran to the fort. When she dashed back, they realized she was running supplies and shot at her. She came back with only one grade of powder. Look at surviving horns that can be dated from the French-Indian Wars. They were predominantly large horns and only large horns. No small priming powder horns. While the caliber decreased as did the horns of the Revolution, still there's only one horn.
It wasn't until the later period (perhaps 1790) and definitely by the War of 1812 that two horns were carried. By then even the British riflemen carried two powder horns - one for priming and one for charging (as well as a cartridge box if they were pressed for time).
Nobody is going to question you if you use one or two horns. I use a small priming device myself. Wait for Wallace Gusler's book to come out and provided he doesn't fall off another cliff from rock climbing (actually it was a good thing b/c they found a tumor and removed it - funny how something bad can be something good) and it will be the definitive book on the early Virginia rifle. A lot of original research is going into it including reading of court records, ledgers, newspapers. Well worth the wait.
I should add that Williamsburg is trying (and one my classmates is offering the loan of the camera) to get a high speed camera to film the flintlock in action. Earlier studies by them suggests that the larger grain powder actually captures the sparks better. The sparks strike from the frizzen and shower down into the pan. Sometimes the strike down and bounce right back up (slow motion photography shows this). But, they're waiting for more tests to confirm it. Studying this ancient technology is quite exciting.
BTW, you can send that frizzen to a gunsmith who will dip it into casenite and reharden it. Or if you have a big enough torch, do it yourself. Afterwards, polish it (the non-strike side) with emery paper or steel wool to restore the white metal look. Leave the dark side dark. It'll get torn up soon enough.
