The 75 mm Gun was a French design from the First World War. Britain purchased a number of these from America in 1940 to fill the gap in their field gun arsenal. Although obsolescent they were still serviceable and in British service were designated Ordnance QF 75 mm. All were supplied on their standard American pattern field carriages but a number of Mark 1’s were modified. This consisted of removing the wheels, axle and traversing gear and cutting off most of the trail. What was left was then mounted on a pedestal to become the Mounting 75 mm Mark 1. This was used as a Beach Defence weapon. Three different patterns were purchased. These were the M1897, M1916 and M1917 (see below). The 75 mm Gun in all its forms were declared obsolete in March 1945 but the pedestal mount was not disposed of until May 1946.
Gun
Mark-1 (American M1897)
Original French purchase. Breech block rotated 120°
Converted Mark-1 (American M1917)
British 18 pdr relined to 75 mm & chambered for French ammo
Converted Mark-1* (American M1917)
As above but on M1917-A1 carriage
“S” Mark-2 (American M1916)
American designed M1916 gun
“S” Mark-2* (American M1916-A1)
Recoil system changed to hydropneumatic
Mark-1 – M1897
Gun
M1897
Original French design. Breech block rotated 120°
M1897-A1
As M1897 but of American manufacture
M1897-A2
No muzzle hoops or jacket. Breech rotated 156°
M1897-A3
As A2 with slight modifications for M1 A2 Carriage
This was the British 18 pdr gun Marks 1 to 2* relined to 75 mm calibre. It was chambered for French ammunition
Carriage
Mark-1 (M1917)
British wooden wheeled, pole trail
Mark-1* (M1917A1)
Steel wheels & pneumatic tyres
Data Converted Mark-1*
Weight of gun & breech mechanism
995 lbs
Total length
88.2 inches
Length of bore
84 inches (28.5 calibres)
Rifling
Increasing, right hand, 0 at breech to 1/25.4 9.72 inches from muzzle, then uniform
Breech mechanism
Interrupted screw, percussion fired
Elevation
-5° to +16°
Traverse
4° left & right
Recoil system
Hydro-spring, constant 49 inches
Weight in action
2,990 lbs
Performance Converted Mark-1
Firing standard 14.7 lb shell
Muzzle velocity
1,900 feet/second
Maximum range
12,490 yards
Ammunition
Fixed, cased charge
There was a wide variety of shells, standardised over the years since 1917. Most of the older ammunition designs were sent to Britain in 1940. This suited the older guns that had been purchased. The older shells were copied from the French designs. They had blunt heads, square bases & protuberant fuses. Fuses were the American PD M46 & M47 types.
