Here's the formula - 5 parts potassium clorate, 1 part sulfer, 1 part charcoal.
: I used this for my own percussion caps, combined & mixed into a slurry, then one drop per cap from the Forester tap-o-cap.
: I got this formula from my book on Underhammer guns. I wrote about this to the Association of Primitive Riflemen, back in the 80's or 70's - can't remember. I received a letter from a chemical engineer who stated that this formula was OUTLAWED as a priming mixture in 1898 due to it being unstable. It certainly was explosive & made a nice hot cap, however a bit corrosive if not cleaned same day as shooting, even in a dry climate.
It was stated that a change in climate could detonate it. Well, mine never has and there still is a bunch of pwder around somewhere in the shop - perhaps 1/4 ounce of it in a tiny glass bottle for 20 years. I used sublimed sulfer(flour of sulfer) which is more highly refined than anything they had. I also used, instead of charcoal, ground up briquets for their gritty properties, which is what the charcoal was for, apparently. The stuff worked great, but was corrosive and worlds better than kids toy caps. Oh, BTW- this compound was used in the tube locks, probably Forsythe's scent bottle, and for pill locks & percussion caps. When dry, it is a grey dust. I've even ground small chunks in a mortor and pestile without detonating it. A smack with a hammer, will detonate this stuff, even in a fine powder. Quite a mix, it's chemicals are all available at a pharmacy, except perhaps the briquets - be warned, in it's original formula, it is sensitive to all changes, atmospheric and impact & may detonate withou warning- danger, danger. I really liked it. OK - so lock me up already.- HA!
Daryl