No 69 grenade The British No 69 was a hand grenade developed and used during World War II . It was adopted into service due to the need for a grenade with smaller destructive radius than the No 36M " Mills bomb " . This allowed the thrower to use a grenade even when there was little in the way of defensive cover . In contrast , the much greater destructive radius of the Mills bomb than its throwing range forced users to choose their throwing point carefully , in order to ensure that they would not be wounded by their own grenade . The shell of the No 69 grenade was composed entirely of the hard plastic , Bakelite , which shattered without producing fragments like a metal bodied grenade . Metal fragmenting sleeves were available to increase the grenade ' s lethality . Using the No 69 bomb was very simple : the screw - off cap was removed and discarded , and the grenade was then thrown . When the grenade was thrown , a linen tape with a curved lead weight on the end automatically unwrapped in flight , freeing a ball - bearing inside the fuze . In this manner the " all - ways fuze " was armed in flight and the grenade exploded on impact ; and like the Gammon grenade , which used the same fuze design , it was withdrawn from service soon after the Second World War ended . All - ways fuze . The No 69 was the first British device to make use of the " all - ways fuze " later seen in the No 82 Gammon bomb , the No 73 Thermos bomb and the No 77 smoke grenade . The " Allways " fuze is an impact - only fuze . The term " Allways " refers to the fact that all of the possible ways in which the grenade could hit a target were guaranteed to trigger detonation . Normally , impact - detonated munitions must hit the target with a particular point of impact ( i . e . perpendicular to the fuze mechanism ) in order to detonate . In contrast , no matter which way the No 69 grenade hit the target ( e . g . landing on its base , or sideways or upside down ) it would still explode . The All - ways fuze was composed of a free floating striker and detonator combination held apart by a weak spring . On top of this assembly was a steel ball bearing pressed against a conical housing by the striker . Any impact in the vertical axis would impart acceleration to either the striker or the detonator causing the firing pin to contact and ignite the detonator . Any impact in the horizontal axis would cause the ball bearing to follow the slope of the conical housing converting the horizontal acceleration into a vertical one touching off the detonator as before . The fuze was worked by the user first unscrewing a plastic cap to expose a long , narrow cloth streamer with a curved lead weight attached to the end . Upon release from the hand or projector the weighted streamer would catch the air and quickly unwind from the top of the grenade eventually withdrawing a loose safety pin from the fuze . With the pin removed the striker and detonator would be free to come into contact , which would the happen due to the force of impact when the grenade struck a hard surface . The all - ways fuze had a minor design defect in that the hard steel ball bearing would be propelled away from the explosion as a piece of shrapnel . When used in an " offensive " application such as the No 69 grenade where the user was not required to take cover before throwing , there was a chance that the user could be struck and injured by the fast moving ball bearing . According to military author Ian V . Hogg , this problem led to restrictions in the use of the grenade as practice ordinance .