Adobe .PDF - Thompson Center Arms

Black PowderAnd Pyrodex ®Make no mistake about it, Black Powder or an approved BlackPowder Substitute such as Pyrodex® are the only propellant powdersthat are safe to use in a muzzleloading firearm. Oh, you will hear, or possiblyread, advice to the contrary but don’t follow it for you will never hear suchadvice from a competent source.The reason for using a low yield powder such as Black Powder or Pyrodexis quite basic and it is related to firearm design. When used as a propellant,Black Powder or Pyrodex generates a relatively low breech pressure. Replicafirearms, even with their modern steel barrels, are not designed to withstandthe high pressures produced by a Smokeless Powder charge. Think about it fora minute and you will understand why. The ignition hole in a muzzleloadingfirearm is a direct port into the combustion chamber. This port is sealed onlyby the thin foil of a cap and weight of the hammer in the cap lock model. Inthe flint lock design this port is not sealed at all. The high pressure of a SmokelessPowder charge would destroy this ignition system and the gun itself.To avoid any misunderstanding on the part of the reader let us explain furtherwhy Smokeless Powder cannot be used in a muzzleloader in any quantity.People who become interested in muzzleloading tend to research and toseek out some of the early journals which describe loading implements, componentsand powders of yesterday. Reading these old books can be pleasurable.Never assume, however, that obsolete printed material has a safe applicationin today’s world.In the early days of the breech loader there were powders manufacturedwhich were called “Bulk Smokeless”. These powders were measured by the volumeand used interchangeably with Black Powder in early cartridge firearms.Even in their time these powders were never used in muzzleloading firearms.Early “Bulk Smokeless” powders are not available today and, even if theywere, their erratic performance (extreme variations in pressure) would notmeet current industry standards. By modern standards, such early bulk powderswere unsafe, even in the days of their use. The same type of misinformationexists concerning “duplex loads” or the mixing of Smokeless Powder withquantities of Black Powder. This practice was popular in the days of the earlybreech loaders. It was dangerous then and it is even more dangerous now formodern Smokeless Powders are far more complex in their composition.All presently available Smokeless Powders are designed for use withmetallic cartridges and shotshells in strong modern breech loading firearms.They should never be used in a muzzleloading firearm of any type.Some of these powders are “Black” in color making proper identification ex-11