A Profuse Powder Perusal
The problem with blackpowder, and the "fake" blackpowder substitutes, from a safety and a performance standpoint is largely due to its porosity and resultant extremely fragile particle structure. By being uncoated, porous, and easily broken up it is highly impact sensitive. A few grains of blackpowder in a baggie hit with a hammer in your garage can make that "memorable" for you. The safety issue is clear. The porosity of the powder allows it to suck moisture out of the air, and that is a field performance issue true to the adage "keep your powder dry." The negative qualities of combined impact sensitivity, self-sustaining ignition, and moisture attracting heavy reside left by the filthy stuff combine to make it problem-filled propellant.
The easy ignition offsets some of the moisture suckage; as few readily propellants ignite easier, it is still used in some military / industrial applications today as few products displace it. What is more difficult to manage is the corrosion guaranteed to start just as soon as you take your fouling shot in your muzzleloader, as well as the impact issue and the easy ignition (cook-off) propensity that only have to happen once in your lifetime to be of great concern. The heavy fouling left behind after each shot may cause barrel pressures to skyrocket in subsequent shots without barrel cleaning. Not a major issue in muzzleloaders designed to accommodate this, it is a a known problem in marginal-barreled frontloaders that do not have this as a designed-in, tested-in consideration.
Moving along to our 125 year-old variation of energetic Ping-Pong balls, there are powders not suited to the Savage 10ML-II application. The same coatings that make smokeless propellants inherently safe must be burned away for proper ignition. You may have read references to the various "thicknesses" or types of coatings in smokeless propellants-- but that is not really relevant to our ignition characteristics in the Savage 10ML-II. It is the percentage of coatings in a given powder by weight that can make them too hard to ignite for low-resistance use (as in a low coefficient of friction sabot). This should explain why "ball powder" is a poor choice for muzzleloading. The small ball of powder is completely ensconced with coating, and in relationship to its weight, is one of the highest percentage of coating powders. Hopefully, this should explain why they may have ignition problems in a muzzleloading application-there is just too much coating to burn though without the direct resistance (shot start pressure) of a gilding metal jacket bullet being forced into rifling from a cartridge. The "shot start" pressure in a .30-06 Springfield can easily exceed 10,000 PSI. We don't have anywhere near that figure to work with in a load from the muzzle application, and it looks like we never will. The severe limitation of "loads from the muzzle" (we really want easily loads from the muzzle) prohibits that. As a sidebar, most smokeless propellants are assumed to be "progressively" burning propellants. In a general sense, that is true that they continue to produce gas as they travel down the bore. From a technical standpoint, it is not true. In the case of ball powder, once the stabilizing coating is burned and the powder is properly ignited, you have maximum surface area producing gas. From that point on, the surface area of ball powder diminishes, and the gas-producing ability shrinks. Ball powder becomes a degressively burning propellant, producing less and less gas as it travels down the barrel in concert with its ever-decreasing surface area shrinkage.
Most extruded powders have a "progressive curve" and a degressive curve. The point of intersection of these curves are contingent somewhat on ambient conditions and application. To address Savage 10ML-II powders, the comparatively tough, position insensitive Accurate Arms 5744 reigns supreme in terms of overall use for 200 to 300 grain projectiles. As a double-based powder, it is more flexible than its single based counterparts in the Savage application.
For best performance, single based powders must compliment the projectile weight (sabot and bullet) for optimum performance. That indicates Vihtavouri N110 for 250 grain bullets; Vihtavouri N120 for 300 gr. class projectiles, and Accurate Arms 2015 for 350-400 grain projectiles. Assuming the same single base of nitrated cellulose (more nitration of the cellulose means more energy potential) as we go with the more heavily retarded slower powders due to both geometry and coating percentage, their mainstream usefulness becomes less and less. Using the same Savage 10ML-II ignition system, our ability to properly ignite taller and taller columns of more heavily retarded powders becomes a realistic field use limitation, along with increased recoil, and a coinciding reduction in useable barrel length.
This monograph does not attempt to encompass all variables, but hopes to touch upon the primary considerations for what we all want: loads with supreme reliability that build supreme confidence.
© July, 2005 by Randy Wakeman
