Doc White, beloved by all who know him, generously offered his candid commentary in this interview, conducted over a period of several months. Doc White is a rare gem, and his thoughts and approaches have affected and directed the world of muzzleloading second to no one.

RW: I'm of the opinion that the corrosiveness of blackpowder and synthetic substitutes has been overstated. Not to suggest that blackpowder arms should not be cleaned after a shooting session, and cleaned well, but the literature seems to have a void as to what actually happens due to the fouling residue beyond its hygroscopic nature. After all, Webster defines it as "to eat away by degrees as if by gnawing; especially: to wear away gradually usually by chemical action <the metal was corroded beyond repair>." What are your thoughts and experiences as to the real-world metal wearing abilities of blackpowder, Pyrodex, and Triple Seven propellants?

DOC: The residues left from black powder combustion include sulfates, carbonates and nitrates, all in the presence of water due to hygroscopicity of the fired residue. The sulfates can form sulfuric acid, the nitrates nitric acid, and the carbonates the weak carbonic acid. All can eat away at metal if left long enough. Fortunately, the amounts left in the barrel are usually small and relatively weak, and are only a problem if left for a long time. This is in addition to the rusting effect of the water, which is the worst problem, relatively speaking.

Pyrodex is basically black powder enhanced with chlorates (an old time trick used as early as 1800), which adds the problems associated with hydrochloric acid. This acid is the reason Pyrodex can etch stainless barrels. The result is, as more water vapor is thrown into the residue, the worse the problem; not only because of water-induced rust, but also from acid etching.

Goex Clean Shot is fructose fueled but I’m betting they have added chlorates to spice it up. I don’t know what 777 is fueled by, but it looks like a sugar under the microscope and acts like an ascorbic acid (which is a weakly acidic sugar) based powder, also containing chlorates, I’ll bet.

The interesting thing about all these fuels is that all are far more hygroscopic in the natural state than is charcoal. The burned fuel (or I should say partially burned, because only a portion of it actually oxidizes) is equally hygroscopic, making all of them far more capable of sucking water out of the air than the charcoal in black powder.

Do an interesting experiment: take a 20 grain charge of all available powders; put them in spoons, all the same size, and light them all off with a propane torch. Now put all the spoons, complete with residues, in the freezer, each one not touching the others. Leave all of them to freeze. Pick a nice humid day, take them out and watch them. All will collect water from the air like sponges, but the worst will be the fructose-based residue, next the ascorbic acid (not a lot of difference), and best the black powder and Pyrodex. This explains why 777 and Clean Shot can be cleaned with just water, it’s because they are so darned hygroscopic and soluble in water.

Better yet, take any of the newer powders hunting on a good, cold, humid Missouri day. Shoot the gun at least once, and then watch the water accumulate in the action. Does it collect like that in the chamber where there is a new powder charge? You better believe it. Does that make the rifle that uses black powder based substitutes better? Yup! How about the systems that lockout the water better? The answer is obvious. Another set of reasons I like Pyrodex and #11 caps on Doc-engineered nipples!

So my answer is obtuse, none are much of a problem if you keep the gun clean, all are somewhat a problem if you leave the gun loaded for a long time in humid conditions. All are a problem if the gun is not water vapor proof. If in doubt, shoot it out, then clean it and reload from fresh the next day.

RW: It would not exactly be a stretch to say that Pyrodex "P" is your general muzzleloading propellant of choice for the guns that can handle it, and not completely by chance that "P" is the primary recommended propellant for the guns that bear your name?

DOC: Pyrodex P is the propellant of choice for White rifles using #11 or musket caps, not for those using the 209 primer. I prefer Select in that case. I prefer Pyrodex, in general, because it is less hygroscopic than the other substitutes, even though that makes it clean up with somewhat more difficulty.

I prefer P in cap guns because my ballistic experiments show that it ignites more easily, is more uniform to pour as well as to ignite and burn, produces demonstrably more uniform pressure curves with more uniform area "under the curve," produces less variation in velocity and is more accurate (in general) in White rifles than the other subs. (With the exception of "Triple 7," which I have not worked with sufficiently to make a definitive statement.)

Black powder is even better in some categories, especially velocity variation, but is way too dirty to function with my system unless the barrel is cleaned between shots. I use Swiss BP for serious target shooting and clean between shots, by the way. Frankly the difference is often minuscule and of little account, except in the case of long, hard hunts far from support systems, in wet weather, or for critters that might turn on you, or where such critters exist even if not hunted. Sheep in the Cassias, where grizzlies abound, is one example.

RW: Blackpowder has never been shown to respond greatly to barrel pressure upon firing, yet Pyrodex apparently does. Ian McMurchy was able to get higher Pyrodex propelled velocities, using equivalent 100 grain charges, using heavier bullets due to this. Have you looked at the pressure curves between those two propellants, as well the Pyrodex pellets, and discovered anything of note?

DOC: The pressure curve of black powder is quite spiky while that of Pyrodex is wider and more rounded. Pellets are even wider and more rounded yet, with absolute pressures being the same. This means that the moment of force on the bullet is prolonged with Pyrodex and pellets, thus the acceleration phase of internal bullet flight is longer and somewhat higher velocities are obtainable with similar weights/volumes equivalent.

Doc White's company is White Muzzleloading, and can be found at www.whitemuzzleloading.com. Send your thanks to Doc, and don't forget to explore Doc White's many unique "Doc-accurized" rifles--hand tuned in a way only the touch of the good Doctor can possibly provide.

Parts 1, 3, 4 and 5 of Randy Wakeman's series of interviews with "Doc" White can be found on the Muzzleloader Information Page.