Guessing that Mohaupt's weapons were using the hollow charge principle, the British abandoned negotiations and began development of a rifle grenade based on their own previous work.

The simple fins gave it some stability in the air and, provided the grenade hit the target at the proper angle (90 degrees), the charge would be effective.

The converted rifles were strengthened by adding an extra bolt to secure the breech mechanism to the stock, and by a cord binding which was fastened around the forestock.

[1] However, it proved to be not much better than the inadequate Boys anti-tank rifle and could not be improved as the size of the explosive charge was limited by the diameter of the discharger cup,[6] It was introduced into service with the Home Guard in February 1941 and was retained until the force stood-down in 1944.

[7] A British manual of 1942, reflecting experience gained in the field, stated that the effective range of the grenade was 50 to 70 yards (45 to 65 metres) and would be best employed against the rear armour of enemy tanks after they had been allowed to pass.