Why Tank Guns Were Used On Bombers

Why was a B-25 Mitchell, a medium bomber, equipped with a tank gun?

Why a Tank Gun?

During the late 1930s and early 1940s, the US Army Air Corp was looking for a plane that could do strafing, ground attack, and anti-shipping duties.

Because the development of a new aircraft usually took around 3 to 5 years, the Army Air Corp looked around for options and found the B-25 Mitchell to be just the right choice.

While technically the Mitchell was a bomber, it had the potential to be an excellent anti-shipping aircraft.

Not an Attack Aircraft Just Yet

During this point, the B-25 isn’t an attack aircraft just yet, but a bomber. In the field, what started to be developed was a Strafer variant of the B-25.

The units on the ground fit four to eight .50-cal machine guns which gave them excellent forward fixed firepower for strafing missions in the Pacific.

Results

While this was already considered enough firepower, the Air Force wanted to have the power of a 75 mm for anti-ship missions.

Beyond that, the requirement to attack destroyers was already challenging for the 75mm. But still, they wanted to divert from the .50-cals and install a weapon that with only just a few hits, would have a higher chance of taking out a ship.

With a radar gun sight, at 5,000 to 2,000 yards, it can hit up to 88% with an inexperienced crew against a destroyer-sized silhouette.