# Burn rate

The burning rate r describes the stationary burning of an explosive . It is usually given in mm / s. The pressure dependency of the burn-up of an explosive describes the Vielles law

${\ displaystyle r = ap ^ {n}}$

with a being the exponential factor ([a] = mm / (s · Pa n )), which indicates the influence of temperature on the burning rate, p is the prevailing pressure ([ p ] = Pa ) and n is the dimensionless pressure exponent.

The product of charge density , specific energy and burn rate is explosive (chemistry) .

The many parameters of a propellant charge are the main criteria according to which the propellant charges are selected for the respective purpose.

In short-barreled weapons ( pistols and revolvers ), propellants with a high burn rate (offensive powder) are used. Propellant charges with a high burn rate are also used for shotgun cartridges .

For long guns and those that have to accelerate high projectile masses, slow-burning propellants, so-called progressive powders, are used .

The burning rate is influenced by the following parameters, among others:

• Chemical composition
• Surface texture