Adobe .PDF - Thompson Center Arms

than the cartridge case that is used in its chamber. If the case ruptures, theprimer punctures or if the headspace is altered, hot powder gases underextreme pressure will flow back through every seam in the action possibly destroyingthe firearm and causing injury to the shooter.The propellant charge in a muzzleloader is poured directly into the barrelof the firearm and then compressed by the projectile in the chamber area.Think about this for a minute! Lacking the restraints and protection suppliedby a modern cartridge case, the muzzleloading charge rests directly against thesteel chamber walls and the face of the breech plug. The ignition port in a caplock or flint lock is a simple hole leading directly into the chamber. Certain surfacesof the breech plug and nipple are directly exposed to chamber pressure.Judged by the design standards set for modern firearms, the muzzleloader isextremely primitive. Its design will not tolerate high pressure.The following text applies to the use of your Thompson/Center muzzleloaderwith Black Powder or Pyrodex charges properly restricted to the loadinginformation shown in this booklet. It deals with those conditions which singularlyor cumulatively can affect muzzleloading pressures.For years it has been assumed that it is impossible to overload a firearmusing Black Powder. The theory was that only a certain portion of a heavyBlack Powder charge will burn and that the remaining powder is blown out ofthe bore in unburned condition. This thinking led to the belief the pressurescreated by a Black Powder charge would reach a certain (undetermined) rangeand climb no higher. Our testing indicates that this theory is completelyunfounded. As heavier and heavier charges were loaded, our pressure readingsclimbed accordingly. At no time was there any indication of a leveling offof pressure. Unreasonably heavy charges of Black Powder or an approvedBlack Powder substitute, such as Pyrodex can be dangerous. Restrictyourself to the loads listed in this booklet and start with the lightest loadshown for your particular model and caliber. Bear in mind that the followingconditions can be cumulative. If you load the heaviest charge listedwithout following instructions (working slowly upward), then other conditionssuch as powder fouling, hard projectiles and improper loading,can carry you well beyond the maximum safe pressure range of muzzleloadingfirearms. All propellant powders (depending upon their design andcomposition) will function most efficiently within a given pressure range. Ourtesting indicates that the Black Powder used in our testing operated most efficientlyin or near the 7,000 P.S.I. range. In other words, those charges whichare approximately midway in our loading charts recorded the highest velocityin relation to the lowest pressure. Heavier loading showed marked increasesin pressure for only minor gains in velocity and were less accurate.Fouling in the bore of a muzzleloader will increase pressure. With BlackPowder, consecutive shots without cleaning will display rapid shot-to-shot increasesin pressure, a variation in velocity and a resultant decrease in accuracy.As Black Powder fouling builds in the bore of your muzzleloader, loading19