Improved military rifle powder

[3] Improved military rifle propellants are coated with dinitrotoluene (DNT) to slow initial burning and graphite to minimize static electricity during blending and loading.

Rate of reaction is controlled by heat transfer through the temperature gradient from the luminous reacting gas through the bubbles to the intact colloid.

The Army identified this military rifle propellant as Pyro DG (for diphenylamine, graphited), and 500 tons per day were manufactured by various plants through the first world war.

Charges of low-density "bulk" propellants were often similar to the volumes of gunpowder used in older firearms and reaction rates were less variable at low pressures appropriate for those cartridges;[9] but each batch of military rifle propellant required a different canister label specifying the batch or lot number with the tested charge weight to generate appropriate reaction pressure in intended cartridges.

Orders from countries fighting World War I required determining charges for different European military rifle cartridges, and production volume supported research for improvements.

Improved military rifle propellants included a longitudinal perforation converting each grain to a tube with a progressive burning interior surface allowing a more consistent gas generation rate through the reaction period.

As these propellants became military surplus after the war, large quantities of different batches were blended together to make products with uniform average performance for sale to civilians.