British Bomb, 500 lb Chemical, Mk 1, Mk 2
The 500 pound bomb was of conventional appearance but it was not of the tail ejection type. It had two bursters (one in the nose and one in the tail), which fragmented the case. When filled with mustard gas it was intended to air burst by means of a barometric or M111 clockwork fuze, thereby discharging its contents in the form of a spray.
The difference between the Mark I and Mark II bombs was the method of securing the burster containers in the bomb. Both the Mark I and Mark II bombs could be filled with phosgene but only the Mark I was filled with mustard.
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