The 18-pounder shrapnel shell contained 374 small spherical bullets. A time fuze was set to initiate the shell in the air in front of the target. This blew off the shell nose and fired the bullets forward in a cone like a shotgun – they were effective up to 300 yards from the burst. For maximum effect from the cone of bullets, the angle of descent of the shell had to be flat and not plunging. At a theoretical maximum 20 rounds per minute, it could deliver 7,480 bullets per minute at a far greater range than machine guns. The gunners and officers of Regular Army field artillery batteries were expert at closely supporting the "fire and movement" tactics of the infantry with accurate shrapnel fire.