Historically, such design work has been wide open to the individual experimenter, the resulting "wildcatting" has been most beneficial to the shooting sports and we did not want to dampen that aspect of this game. Moreover, those who had formerly attempted to benefit from the patenting of a specific cartridge (or chamber) design were effectively foiled by the simple fact that any minor design change – e. g., a difference of a few thousandths of an inch in any pertinent dimension – constituted the creation of a "new" chambering, one that would not be covered by any dimensionally-based patent.
However, the situation with our invention is quite different. Because our effort is based upon design features, rather than specific dimensions, and because it incorporates unique parametric design characteristics (such as shoulder design), dimensionally-specific limitations do not apply – cartridges based upon minor design alterations of an SMc design will still incorporate the key (patented) design characteristics and will, therefore, still be covered by this precept. Moreover, this entire concept falls under the province of intellectual property – we have gone where none has gone before in development of idealized cartridge (or chamber) designs. Chiefly for these reasons, we decided to undertake the expense of patenting these concepts.
Theory
For various
reasons, having to do with the complexity of issues involved, concerns
over patent issues and simple lack of available space, the following
discussion is not fully developed and it is limited in scope and completeness.
We are satisfied that we can demonstrate each of the principles involved
and that we can do so, based upon fundamental principles or derivatives
thereof.
As an overview, the critical issue is what happens to a powder charge after the primer ignites. In a typical rifle cartridge it is proven that the primer never directly ignites every granule in the charge – some portion of the charge, which is a continuous mass located most distal from the primer (behind the bullet), is merely compressed by that blast. Henceforth we will refer to this heterogeneous mass (granules and entrained gases forming an essentially impermeable mass) as the "propellant mass," therewith the analogy with solid rocket motors. This mass initially ignites only along the rear face. This gives two distinct burning regimes – those granules ignited along the entire surface and those burning only along the exposed (rearward) face of the propellant mass.
The former will burn in accordance with well-understood characteristics related to adsorbed deterrent surface treatments and confining pressure (temperature). The latter will burn as a function of confining pressure and the bulk burning rate of the average granule composition (with a significant increase in effective burning rate resulting from increased exposed surface area, due to continuous exposure of included voids and differential burning rate within the exposed granule layer – this burning face will retain a texture, which will increase surface area).
Failure of the primer to
ignite granules within the compressed propellant mass stems from three
distinct factors:
1. no significant pathway exists whereby primer-generated
gases, or those from nascent propellant ignition, can freely pass
through the charge mass – case, barrel and bullet provide a nearly
perfect seal in front of and to the sides of this mass (this eliminates
significant heat transfer into the propellant mass);
2. squeezing of
propellant mass (granule deformation and compression of entrained
gases) soon seals off any existing permeability so that energetic
gases cannot continue to infiltrate this mass,