The Sherman Firefly was a British variation of the M4 Sherman tank, fitted with the more powerful 17 pounder main gun.

Fireflies were introduced to British armoured divisions in 1944 in preparation for the Normandy landings. After discussion it was decided to employ Fireflies spread between every troop (platoon) of each tank battallion, rather than forming special Firefly troops (platoons) or squadrons (companies).

They were among the few Allied tanks capable of taking on the German Panzer V (Panther) and Panzer VI (Tiger) tanks. Though no more well-armored than most M4 versions, the 17 pounder gun offered far better performance then the standard 6 pounder . Even using the regular APC round it could penetrate the front armor of a Tiger I at over 1,000 meters; with the more advanced rounds that became common towards the end of war, such as APDS or APCBC, it could penetrate at over 2,000 meters.

M4A4 VC Firefly

• Length: 19 ft 4 in (5.89 m)
• Width: 8 ft 7 in (2.62 m)
• Height: 9 ft (2.75 m)
• Weight:
• Speed: 25 mph (40 km/h)
• Range: 120 miles (193 km)
• Crew: 4
• Armament:
  • Primary: 76 mm (17 pounder) Gun
  • Secondary:
    • One .50 caliber (12.7 mm) Browning M2 MG
    • One .30 caliber (7.62 mm) Browning M1919 MG
• Power plant: Chrysler Multibank 30 cylinder (5 x inline-6) gasoline