British 5.5-Inch Mark IV Field Gun

British 5.5-Inch Mark IV Field Gun. . The "Five Five" entered service in the summer of 1941 and saw heavy use with British and Commonwealth Armies in World War II, the Korean War and other conflicts into the 1970s. Developed during the 1930's, the gun was designed to replace the 6-inch howitzer. The gun featured a pair of hydro-pneumatic equilibrators (vertical "horns" on either side of the tube) that kept the tube balanced. A 100-lb. shell, with a maximum range of 16,200 yards, was initially used. In 1944, an 82-lb. shell was introduced that gave both more explosive power and a longer range out to 18,100 yards. It became the standard medium British gun at Corps and Army Group level for the remainder of World War II. It first entered combat with the 8th Army in North Africa. During the war, a regiment consisted of 16 guns organized in two batteries. Between D-Day and the German surrender, the "Five Five" fired 2,610,747 rounds. The "Five Five" was produced in four different Marks, with the first three serving during World War II and the fourth introduced after the war. The differences between the four Marks were primarily in construction with rivets being replaced by welding., Caliber - 5.5 in. - 140 mm , Weight - 13,646 lbs. - 6,190 kg , Range - 18,100 yds. - 16,550 m , Shell Weight - 80 lbs. - 36.3 kg , Muzzle Velocity - 1,950 ft/sec. - 511 m/sec. , Elevation - (-5 to + 45 degrees) - (- 90 to + 800 mils) , Traverse - 60 degrees - 1,020 mils , Rate of Fire - 3 rpm , CCN# 107692