Sherman Stories #2: The Potent Firefly


By 1943, thousands of Shermans had already made their mark in North Africa and on the Eastern Front. Yet there quickly came an urgent call for designers to rework the M4 into a machine capable of challenging the German Tiger I and Panther. The solution? To affix a monumental 17-pounder gun on a redesigned Sherman and rapidly steamroll it out the factory doors. What emerged was the powerful VI Sherman Firefly , ready to take on German defenders during and after the successful D-Day invasion.

Join Richard "The Challenger" Cutland as he guides you through the development process and takes a closer look at the beautifully restored historic vehicles at The Tank Museum in Bovington, U.K.

The video was also shown during Tankfest Online 2021. Check out the recording on Twitch or YouTube if you missed the event.

Calls to fit a 17-pounder gun to an Allied tank were not new. Unfortunately, tank development was a notoriously long and arduous process, and most tank hulls and turrets could not handle such a brutal recoil. Engineers initially modified the VI Cromwell as part of the Challenger project, an initiative scrapped after it became plagued by technical problems and production issues.

With the Allies preparing to land in Normandy, they desperately needed a tank to take on the German heavies. British designers therefore turned to the well-established and reliable M4 Sherman. The existing turret mechanisms would not suffice, so the recoil mechanism was completely redesigned. The recoil cylinders were shortened and placed on both sides of the gun to take advantage of the Sherman's turret width. A new mantlet and barrel were added, and the radio was remounted outside the turret in a specially built box. The co-driver position was removed and the vacant space was occupied by 77 rounds of ammunition.

The design wasn't a perfect fix. The powerful blast created a bright muzzle flash, and the resulting cloud of dust and dirt gave away its position while also temporarily blinding the crew. Meanwhile, the feared gun became the prime target of enemy fire, so crews used various means to try disguising it. Nevertheless, fresh battle tactics and a reliance on close support paved the way for their survival and success on the Western Front. Each tank platoon featured two Fireflys to deliver that knockout blow to German heavies, as the new gun could penetrate 163 mm of armor at a distance of 500 m and 150 mm of armor at 1,000 m.

Check out the first video on the M4 Sherman, and stay tuned for the next installments of our Sherman Stories next week featuring the Fury.

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