Took my Walker replica out this afternoon to see how it handled Pyrodex, which I'd never shot. I've only had real blackpowder till my supply ran out a couple of days ago. Had lots of fun shooting the Walker (which is now lying, all cleaned up and oiled, across my lap.) The Pyrodex works fine and makes a nice blast, but alas, it doesn't make the huge fireball out of the muzzle that makes the Walker so fun to shoot with blackpowder! I was keenly disappointed in its flashlessness. The Pyrodex doesn't quite have the same smell, either, though it's smoky and sulfurous. The smoke didn't seem quite as dense as that of blackpowder. It's a much finer granulation than blackpowder of similar burning rate; this RS is supposed to be equivalent to FFg, and it looks much finer than FFFg. It's gray like graphite instead of black. The fouling is a light gray, very dry stuff. It's definitely harder to ignite than black. The first 6 shots, fired without cleaning the residual oil out of the nipples and chamber bases, produced hangfires just like normal flintlock operation. Pow-BOOM! Subsequent shots went off quickly with the percussion cap not heard separately from the shot. It's much more compressible than blackpowder. I shot some of the old style long conical bullets I'd tried the other day with the last of the blackpowder; I'd had to cut back the charge to 45 grains from a volumetric powder measure to get those to seat, but they'd easily seat over the same volumetric 60 grains of Pyrodex I was using with the little .445" balls. Wheel bearing grease works excellently as a lube with this stuff just as it does with the black. Fouling was modest even after 66 shots, and leading wasn't a problem with either the wheelweight bullets or the pure lead balls. Those conical bullets were an experiment I won't likely repeat, as casting with the brass mould is too difficult and it was hard to get good looking bullets from it. I guess I might buy one of the Lee moulds that casts similar bullets sometime, but balls work fine.

Do you happen to know what the general formulation of Pyrodex is? It's supposed to be a "modified blackpowder."

I'm still trying to find a source of blackpowder, as my flintlock rifle's out of action without it. None of the stores in the area will carry it anymore, due to the regulatory hassles.

I've been considerably mistaken about the composition of Pyrodex. The MSDS for it on Hodgdon's site lists the "hazardous ingredients" potassium nitrate, potassium perchlorate, charcoal and sulfur. It avers that the other ingredients are trade secrets, but may be revealed under some Federal law cited therein.



The patent number Pyrodex is produced under is 4,128,443. Go to the U.S. Patent Office's site here: http://patft.uspto.gov/netahtml/srchnum.htm and type in that number. You'll get the full text of the Pyrodex patent. It's a most interesting document. It describes about every possible combination of solid oxidizers and fuels, but the sole claim made in the patent is that retaining a certain percentage of water in the mixture moderates the combustion, leading to lower pressures and higher velocities. I suspect that the actual composition is something similar to the one listed in #7: 45 parts of potassium nitrate, 9 parts of charcoal, 6 parts of sulfur, 19 parts of potassium perchlorate, 11 parts of sodium benzoate, 6 parts of dicyanamide and from 1 to 4 parts of water. The dicyanamide would be the thing making the burnt feathers smell and possibly nitrosamines. There also are items like binder gums and waxes listed in the description, and they're likely found in the commercial product. Basically, it's a mix of common blackpowder and a pyrotechnic "whistle mix."



One reason I can see that Hodgdon is very secretive about the composition is that this stuff's residue is highly corrosive, containing a large amount of KCl, way in excess of that produced by corrosive primers. Prompt cleanup with hot water gets rid of that, of course, but shooters tend to be "gunshy" about chloride salts in their guns.



I've found several references claiming that Pyrodex burns at a temperature of 4000� F. That's a good bit hotter than BP, but cooler than any smokeless, even WC872 which is about the coolest of them all. (2700K.) I think the flashlessness must be mainly due to combustion of the fuels being very complete, as opposed to BP leaving much of the charcoal unburned till exhaust. KCl is of course a vapor at these high temperatures and contributes to the propulsive effect, plus it is a potent inhibitor of free radical chain reactions in gaseous combustion.



At any rate, my Walker shoots well with Pyrodex, but I miss my flash.