Propellant Window

The data provided contains all necessary values to describe the characteristics of a given propellant. All fields are editable, but it is highly recommended to refrain from doing so.

The propellant window contains the following fields:

• Propellant (Powder) Selection (first drop-down)
  By selecting a powder from the propellants database, all values ar set to manufacturers standards.

• Spec. Explosive Heat (Qex)
  This value (Qex) describes the total contained amount of explosive energy of the powder taken by caliometric measurements.

• Isotropic Exponent (k)
  This value (κ) describes the heat-capacity of gases created by the powder at constant pressure (Cp) and volume (Cv)

• Combution Coefficient (Ba)
  This value (Ba) describes the “vitality” of the powder during the ignition process.

• prog./degr. Coefficient (a0)
  This value (a0) is a reference, whether the powder reacts progressive or degressive when combusted.

• Transition Limit (z1)
  This value (z1) is the boundary, where the powders progressive combustion translates into primary-degressive combustion.

• Transition Limit (z2)
  This value (z2) is the boundary, where the powders primary-degressive combustion translates into secondary-degressive combustion

• Material Density (Pc)
  The density of material (pc) describes the mass/density of the material, the powder is made from.

• Bulk Density (Pcd)
  Bulk density (pcd) describes the mass/density of the powder, in its final physicall appearance per volume (including air pockets in cavities and between flakes or filaments)

• Powder Temperature (Pt)
  The temperature of the propellant. This temperature has some influence of the combustion behaviour of the propellant itself.

• Powder Mass (mc)
  The amount of powder dispensed into a case/round. This is the central editable field to explore changes in pressure, velocity and muzzle energy in the output diagrams to aquire a suitable charge.

• Loading Ladder
  This field is used to tell GRT, if multiple graphs for pressure, velocity and energy should be used in the main output diagram as a load development ladder. If no stepping (=1) is applied selected, only single graphs (corresponding to the selected powder mass) for pressure, energy and velocity will be drawn. If stepping (n>1) is applied, multiple graphs are generated. Those reflect the maximum charge, based on the selected powder mass and additional n graphs for n times reduced amounts of powder (see step size).

• Step Size
  This defines the offset for the reduced charges in load development ladder mode