Development of the gun and carriage took place during the 1930’s and by 1938 was standardised as the 155 mm Gun M1 on Carriage M1. The carriage was a split trail design on a bogie unit with four dual wheels. In action the bogie was raised by screw jacks leaving the carriage firmly on the ground. The gun was trunnioned well to the rear and balanced by hydropneumatic equilibrators. For transport the gun could be disconnected from the recoil system and pulled back, the breech being clamped to the trail legs. In 1943 the guns began to enter British service under Leand/Lease. By the end of the year the carriage had been successfully adapted to take a British 7.2 inch Howitzer barrel. This, with the new Mark 6 gun became the standard British heavy gun in 21 Army Group.
Gun
M 1
Original design with bushing between breech ring & barrel
M1A1
Breech screw threads cut directly into breech ring. Screwed & shrunk to barrel without bushing
M2
Breech ring attachment simplified
Carriage
M1
Original design. No other types applicable to British use
Data
Weight with breech mechanism
9595 lbs
Total length
290 inches
Length of bore
274.6 inches (45 calibres)
Rifling
48 grooves, uniform Right Hand 1/25
Breech mechanism
Asbury interrupted screw, percussion fired
Elevation
-1º40′ to +63º20′
Traverse
30º right & left
Recoil system
Hydropneumatic, variable 35.7 to 65 inches
Weight in action
30,600 lbs
Performance
Firing standard95 lb HE shell
Muzzle velocity
2,800 feet per second
Maximum range
25,395 yards
Ammunition
Shell, HE, M101
Streamlined shell filled with TNT & fitted with Fuzes PD M51 or TM M67
Shell, Chemical, M104
WP Smoke, FS Smoke or Mustard Gas fillings. The later never issued
Projectile, AP, M112B1
Piercing shell with penetrative & ballistic caps
Propelling charge
Base charge plus one increment. Cordite used in British service
