Peak pressure is reached when burning surface area reaches a maximum in the cartridge keeping in mind that the plug of propellant following the bullet can only burn from the chamber side because of the quenching action of the barrel or brass case neck.
Use of this burn front model for parametric cartridge design has maximized cartridge performance and efficiency beyond any heretofore achieved. This was done by setting D between 2 and 2.3 times bullet diameter and l to more than 0.6 inches plus the compression factor for the propellant. An internal ellipsoidal shoulder angle of 48 to 54 degrees at the neck shoulder juncture was provided, focusing the primer shock wave 0.04 to 0.10 inches from the bullet base to minimize heat loss to the bullet. This maximizes adiabatic heating of the propellant that would normally be the last to burn before the bullet reaches the muzzle.