nitrocellulose mixed propellant fines such as 60 nitrocellulose and 40 nitroglycerin as well as other ratios are satisfactory these commercially available propellants are available in small particle size such as from about 0 010 to about 0 020 inch in diameter other suitable propellants include dinitrotoluene picric acid and nitroquanidine the propellant may also be a mixture of specified propellants one preferred propellant comprises propellant flakes and is offered by hercules incorporated camden n j as the 1500 series propellant the propellant consists of flakes of a size which will pass through a 30 mesh screen and have the composition 30 nitroglycerin and 70 nitrocellulose the flakes may be coated with graphite to improve flow during primer mixing and loading from about 10 to about 50 by weight of an initiating explosive when the amount of initiating explosive is less than 10 the primer mix has too low a brisance ignition of the primer is as a puff rather than an energetic explosion if the content is above 50 the brisance is too high and the initiating explosion too violent the content of the sensitizer is from 2 to about 10 by weight below 2 the sensitivity is low and the frequency of primer 34 no fire 34 failures increases increasing the amount of sensitizer above 10 does not contribute to any additional increase in sensitivity the amount of propellant is from 3 to 30 a propellant content of less than about 3 lacks sufficient brisance to ignite the main charge above 30 the brisance is too high and the primer too energetic.