The 25pdr SP, tracked, Sexton was developed during World war II, as one the few Canadian designed vehicles that served during the war. The production of Sextons started when USA’s production of M4 sherman’s was up and running resulting in the decreasing production of Grizzly and Ram tanks and shifting production over to Sexton’s.
The Sexton Mk1 was created by modifying a Ram tank chassis to accommodate the 25pdr gun. They made around 124 (number varies depending on source but its all around 123-125) for the Canadian Government. Following that order the British Government ordered 300 but with the chassis being the M4 chassis, the chassis chosen was the Grizzly chassis as the America made M4 chassis and the Canadian made Grizzly chassis have a lot of similarities between each other. This new chassis went under the name Sexton II or Sexton Mk II.
Trails of the vehicle started in June of 1942, once trails were over (unsure on date) production of the vehicle started. Almost a year later in May of 1943 the vehicle got the official designation Sexton, in the summer of 1943 the British order of what would be named the Sexton II was ordered. The vehicle then entered its first combat in September of 1943 in Italy.
During the War Sexton’s were used by Canada, United Kingdom, Poland and South Africa.
During Normandy there was also some of the vehicle that were modified to be stabilized in their landing craft enough so that they could fire from them to provide artillery support to the landing force. (I have trouble finding more sources on this or photos so I’m unsure if this is true or not)
There was 2,150 Sexton SPG’s made by the end of 1945
Sexton tanks were manufactured by Montreal Locomotive Works they were also responsible for manufacturing the Ram tank
Source:RamTank.ca - Sexton
Ordnance Q.F. 25pdr Mk1/Mk2/Mk3 (sources vary)
According to Design Records
Able to store up to 112 shells.
87 - H.E./Smoke
18 - A.P.
Gun Elevation: 40°
Gun Depression: 9° (not sure if this is suppose to be -9)
Gun Traverse: 25° Left and 15° Right
Maximum Speed: 25 miles an hour ( 40.23 km per hour)
Additional Canvas cover for the crew was also standard to have in the vehicle/
1/2" Bullet Proof steel on the sides and the rear
3/4" Bullet Proof steel in the front
Hull: Ram Tank
Front: 3" - 2"
Rear: 1 1/2"
Sides: 2 1/2" - 1 1/4"
Bottom: Front: 1" Rear: 1/2"
Close Fire Support: The Sexton Self-Propelled Gun and the 23rd Field Regiment, 1942-45 Link to PDF (Really Good source)