Coastal Command Boeing B-17 Fortress IIA FK185 was modified with an all-electric B.16 mounting built by Bristol installed in the nose.

[6] Early operations by the Desert Air Force in the North Africa campaign demonstrated that existing weapons were ineffective against newer German vehicles like the Panzer III medium tank.

In April 1941 a group formed to study the issue, considered a series of 37 and 40 mm weapons including the "S", the Rolls-Royce cannon (belt fed variant), and the US-built M4 autocannon, all firing armour-piercing ammunition.

About 200 BF guns were produced, but after a series of misfires and ammunition explosions,[3][page needed] the decision was made to introduce ground attack variants of the Hawker Hurricane (designated Mark IID) with the "S".

The weight of the guns and ammunition, along with the dust filters and other equipment needed for desert operations, slowed the aircraft by a significant 40 mph (64 km/h).

By October 1941 it was decided that the autocannon would not be suitable in the future, and the same research group turned their attention to rockets, eventually leading to the introduction of the RP-3 in 1943.

This caused the nose to drop, and while flying at a typical altitude of 50 ft (15 m) during the approach, firing without first re-adjusting the flight path was dangerous.

The pilots eventually concluded that the guns could be fired twice before the aircraft flew past the target, although on rare occasions a third shot was possible.

Assessments carried out in South East Asia showed a relatively high level of accuracy: an average of 25% of shots fired at tanks hit their target.