Turning the Sherman into a killer
From the hedgerow of Normandy, France, to the hills of Italy and the plains of Netherlands, the Firefly was one of the few Allied tanks the Germans learned to fear… Among the most potent Allied conversion of the war, and certainly one of the deadliest version of the Sherman, it was a clever -although risky and improvised- move to try to keep up with the latest German tank developments. At that time, the “basic” M4 Sherman equipped the Allies almost exclusively, from the US to the British, Canadian, ANZACS, Free Polish and Free French forces, and its limitations were well known before 1944.
Its basic 75 mm (2.95 in) gun was excellent to deal with other tanks at reasonable ranges and against armor up to 75 mm (2.95 in), or against fortifications and infantry. But facing the latest versions of the Panzer IV, the Panther and Tiger, it was woefully inadequate. However, the British Army had just received the superlative 17 pounder, which proved itself able to nail any known Panzer. Mated with the Sherman, this stopgap combination (before the new generation of Allied tanks could enter service) became lethal, and added its own weight to the Allied effort to secure victory.
Preserved Firefly, showing its camouflaged barrel, as seen in 2008.
The idea of putting the 17 Pounder (76.2 mm/3 in) on a Sherman was long opposed by the Ministry of Supply. It finally happened largely due to the efforts and perseverance of two officers, British Major George Brighty, with the help of Lieutenant Colonel Witheridge, an experienced veteran of the North African campaign and wounded at Gazala. Despite reports and refusals, they managed to pursue the project by themselves and eventually get the concept accepted. Massive delays also began to appear in the development of the official projects which were meant to mount the new gun. Brighty had already made attempts of the conversion at the Lulworth Armoured Fighting School in early 1943. This first version had the whole recoil system removed, locking in effect the gun in place, while the tank bluntly absorbed the recoil. Witheridge joined Brighty due to the doubts of the A30, Cruiser Mark VIII Challenger being ready in time and lobbied actively for the same idea, providing his assistance and solving the recoil problem.
They received a note from the Department of Tank Design to cease their efforts. However, thanks to Witheridge’s connections, they eventually convinced the head of the Royal Armoured Corps. They then won over the Director General of Weapon and Instrument Production, and the Ministry of Supply, who ultimately gave them full support, funding, and an official approval. In October-November 1943 already, enthusiasm and knowledge about the project grew. In early 1944, before the new delays of the Challenger and inability of the Cromwell turret ring to receive the 17 pdr became known, the programme was eventually given the ‘highest priority’ by Winston Churchill himself in preparation for D-Day.
Ex-Dutch Firefly preserved at the Amersfoort Cavalry Museum
About the 17 pounder
This legendary piece of ordnance was the first of the many ROF (Royal Ordnance Factory) cannons which came to fame postwar. These included the rifled L7 105 mm (4.13 in) and later the L11 120 mm (4.72 in) gun that was given to the Chieftain and Challenger. The 17 pounder was a 76.2 mm (3 in) gun with a length of 55 calibres. It had a 2,900 ft/s (880 m/s) muzzle velocity with HE and HEAT rounds and 3,950 ft/s (1,200 m/s) with APDS or Armor Piercing Capped, and Ballistic Capped. These figures allowed it to defeat armor in the range of 120-208 mm (4.72-8.18 in) in thickness at 1,000 m and up to 1,500 m with the APDS.
The design of the gun was ready in 1941 and production started in 1942. It proved itself time and again in Tunisia, Sicily and Italy, with the first action in February 1943. So the idea to have it inside a tank turret was a priority, since the QF 6-pdr was found inadequate by 1943. However, the 17 pounder was long and heavy. It therefore needed much reworking and compromises to have it installed in a turret, and intermediary solutions had to be found. By 1944, the Archer used it, as well as the Achilles (M10 Wolverine), the Challenger, and later the Comet.
17 Pounder ammo rounds being loaded by the crew of a Sherman Firefly. Notice the camouflage nets around the turret, mantlet and gun barrel
The work of genius was that of successfully cramming the heavy gun into a turret it was never designed for. By doing it, W.G.K. Kilbourn, a Vickers engineer, allowed the quick conversion of the most prolific Allied tank. This ensured that no changes in maintenance, supply and transport chains were needed. These were quite critical factors after D-Day.
There were a few changes made to the chassis, most of which were Mk.I hybrids (cast glacis) and Mark Vs, except for the modified ammo cradles and the hull gunner position being eliminated to make room for more ammo. The turret interior was also completely modified. The rear was emptied to allow the gun to recoil and a counterweight was added to the rear to balance the long barrel. This “bustle” now housed the radio, formerly at the back of the turret, and could be accessed by a large hole in the casting. The mantlet was also modified, 13 mm (0.51 in) thicker than the original. The loader also had his position changed. A new hatch had to be cut into the top of the turret over the gunner’s position since the size of the new gun prevented the gunner from using the normal hatch.
But the 17-pdr itself still had a one-meter long recoil course, and the whole recoil system was completely modified. The main recoil cylinders were shortened while additional new cylinders were added to take advantage of the turret width. The gun breech was rotated 90 degrees to allow the loader to sit on the left. The gun cradle also had to be shortened, which caused stability concerns. These were solved by the adoption of a longer untapered section at the base of the barrel. Therefore, the Firefly had it’s custom tailored version of the 17 pdr.
Polish Sherman Firefly at Namur, in Belgium, in 1944
Main Gun penetration figures
Official British War Department test figures show that the 17pdr anti-tank gun firing armor piercing AP rounds would penetrate the following thickness of homogeneous armour plate and these distances: 500 yrds. (457 m) = 119.2 mm; 1000 yrds (914.4 m) = 107.3 mm and 1500 yrds (1371.6 M) = 96.7mm. When firing armor-piercing capped (APC) rounds at face-hardened armor plate these are the test results: 500 yrds. (457 m) = 132.9 mm; 1000 yrds (914.4 m) = 116.5 mm and 1500 yrds (1371.6 M) = 101.7 mm. When fired at sloped armour it was estimated there would have been 80% success at 30 degrees’ angle of attack.
The Firefly in Action
The Firefly was ready in numbers and filled the 21st Army Group’s Armored Brigades in 1944, just in time for D-Day. This was fortunate because Allied intelligence did not anticipate the presence of enemy tanks, of which the numerous Panthers were formidable adversaries for the Sherman.
Ken Tout summed up his impressions about the Firefly, then at the 1st Northamptonshire Yeomanry:
“The Firefly tank is an ordinary Sherman but, in order to accommodate the immense breach of the 17-pounder and to store its massive shells, the co-driver has been eliminated and his little den has been used as storage space. … The flash is so brilliant that both gunner and commander need to blink at the moment of firing. Otherwise they will be blinded for so long that they will not see the shot hit the target. The muzzle flash spurts out so much flame that, after a shot or two, the hedge or undergrowth in front of the tank is likely to start burning. When moving, the gun’s overlap in front or, if traversed, to the side is so long that driver, gunner and commander have to be constantly alert to avoid wrapping the barrel around some apparently distant tree, defenceless lamp-post or inoffensive house”
British Firefly crossing a bridge, Operation Goodwood
Fortunately, the Firefly was also present. The British and Commonwealth units had to face over 70% of all German armor deployed during the Battle of Normandy, including the much-feared SS Panzer units, in particular around Caen. In turn, the Germans learnt to recognise and respect the Firefly, which often became their #1 priority target in most engagements. Such was the damage they inflicted. In response, the crews usually painted the protruding half of the barrel with an effective countershading pattern to try to disguise it as a regular Sherman. A common tactic was to place the Fireflies in good hull-down positions in support of other Shermans, covering them in the advance each time an enemy tank would reveal itself, at least in theory.
Their effectiveness rapidly became legendary, as testified by the most enviable hunting scores of all Allied tanks. On 9 June 1944, Lt. G. K. Henry’s Firefly knocked-out five Panthers from the 12th SS Panzer Division in rapid succession during the defense of Norrey-en-Bessin. Other Shermans were credited with two more, out of a total of 12, successfully repelling the attack. On June 14, Sgt. Harris of the 4th/7th Dragoon Guards destroyed five Panthers around the hamlet of Lingèvres, near Tilly-sur-Seulles, changing position in between. Even the most feared German top ace tank commander, Michael Wittman, was presumably killed by a Canadian Firefly. This famous action was credited to Ekins, the gunner of Sergeant Gordon’s Sherman Firefly from the 1st Northamptonshire Yeomanry, A-Sqn. He destroyed three Tigers in a row, one of which was presumably that of Michael Wittman, near Cintheaux, in August 1944.
Fireflies of the Irish Guards group, operation Market Garden
In total, the 1900+ Fireflies were used by the 4th, 8th, 27th, 33rd Armored Brigades, the Guards Armoured Division and the 7th and 11th Armoured Division in Normandy and north-western Europe, including the Netherlands and Northwestern Germany. In Italy, it was deployed with the British 1st and 6th Armoured Divisions. The Canadians had Fireflies with the 1st (Italy) and 2nd Brigades and in the 4th and 5th Canadian Armoured Divisions, mostly in north-west Europe in 1945. The 1st Czechoslovak Armoured Brigade operated 36 Firefly 1Cs during the siege of Dunkirk in 1944. The 4th New Zealand Armoured Brigade had some during the Italian campaign, as did the Polish 1st Armoured Division (NW Europe) and 2nd Armoured Brigade (Italy), and the 6th South African Armoured Division in Italy. After the war, Fireflies were still used by Italy, Lebanon (until the 1980s), Argentina, Belgium and the Netherlands (until the late 1950s).
Sherman Firefly specifications
|Dimensions (L/w/h)||19’4” (25’6” oa) x 8’8” x 9′ (5.89/7.77 oa x 2.64 x 2.7 m)|
|Total weight, battle ready||37,75 long tons (35.3 tons, 83,224 lbs)|
|Crew||4 (commander, driver, gunner, loader)|
|Propulsion||Multibank/radial petrol engine, 425 hp, 11 hp/ton|
|Top speed||40 km/h (25 mph)|
|Range (road)||193 km (120 mi)|
|Armament||ROF OQF 17 Pdr (3 in/76.2 mm), 77 rounds
Roof cal.50 (12.7 mm) Browning M2
Coaxial cal.30 (7.62 mm) Browning M1919, 5000 rounds
|Armor||90 mm (3.54 in) max, turret front|
|Total production||2000+ in 1944-45|
|For information about abbreviations check the Lexical Index|
Links, Resources & Further Reading
Firefly Ic hybrid from a Polish armored unit, Italy 1944.
British Sherman Firefly Ic, East Riding Yeomanry, 27th Armoured Brigade, Normandy, 6 June 1944
Firefly Ic, 29 Armoured Brigade, 11th Armoured Division, Normandy, summer 1944.
Firefly VC, 14th Regiment, Royal Armoured Corps, 33rd Armoured Brigade, July 1944
Firefly, VC 3rd County of London Yeomanry, 4th Armoured Brigade, Normandy, summer 1944.
Firefly VC, 4/7th Royal Dragoon Guards, 3th Armoured Brigade, France, 1944.
Firefly Mk.VC “Dopo voi”, New Zealand 15th Armoured Regiment, 4th Armoured Brigade, Trieste, Italy, May 1945.
New Zealander Firefly VC “Peacemaker”, 15th Armoured Regiment, 4th Armoured Brigade, Adriatic front, Italy, 1945.
Rare Mk.Ic composite Firefly Tulip, the ultimate tank hunter. It was given RP-3 rockets also used by the Hawker Typhoon.
All Illustrations are by Tank Encyclopedia’s own David Bocquelet.
Chill with this cool Sherman shirt. A portion of the proceeds from this purchase will support Tank Encyclopedia, a military history research project.
American M4 Sherman Tank – Tank Encyclopedia Support Shirt
Give ’em a pounding with your Sherman coming through! A portion of the proceeds from this purchase will support Tank Encyclopedia, a military history research project.
A compilation of little known military history from the 20th century. Including tales of dashing heroes, astounding feats of valour, sheer outrageous luck and the experiences of the average soldier.