Fecha de publicación: 02/03/1976 Fuente: WIPO "pollen" Gas pressure generated during firing of a blank cartridge expands down the ore of a weapon barrel having a pressure relief valve attached to the end thereof and into which the propellant gases are vented to provide barrel recoil and yet prevent residue buildup therein. -GOVT PAR This invention described herein may be manufactured, used and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.