United States Gun Motor Carriage M12

World War 2 Tank and Gun Database

The Gun Motor Carriage M12, it was based on the SP Gun chassis and was in use from 1941.

General Details (SP Artillery)

Specifications
Operational Date(s)	1941
Ordnance classification
Quantity Produced	100
Weight	unknown
Crew	6
M.G's small	n/a
M.G's large(>10mm)	n/a
Length	6.83 mtr
Width	2.69 mtr
Height	2.92 mtr
Engine Details/Performance
Max Road Speed	24 mph
Max Cross Country Speed	12 mph
Range Road	140 miles
Range Cross Country	unknown
Fuel Type	Petrol
Fuel Capacity	unknown
Horse Power	350 hp
Power/Weight	unknown

General Information
The Gun Motor Carriage M12, it was based on the SP Gun chassis and was in use from 1941. Its main armament consisted

Armour Details

Turret
Front	n/a
Side	n/a
Rear	n/a
Top	n/a

Superstructure
Front	36mm	@	45°	(51mm)
Side	20mm	@	0°	(20mm)
Rear	20mm	@	0°	(20mm)
Top	12mm	@	90°	(12mm)

Hull
Front	36mm	@	45°	(51mm)
Side	20mm	@	0°	(20mm)
Rear	20mm	@	0°	(20mm)
Top	12mm	@	90°	(12mm)

Armour (x)mm @ (y)° (Effective mm @ 0°)

Effective Armour - Maximum 51 mm - Minimum 12 mm

About Penetration Figures

All penetration figures in this database are calculated to a common standard based on German WWII testing criteria (complete penetration with functioning fuze). This allows direct comparison between all nations' guns.

Original national test figures would be higher for some nations due to different criteria:

German: 1.00? (baseline - strictest)
British: 1.02? (slightly looser)
American: 1.05? (50% mass through plate)
Soviet: 1.10? (75% mass through plate)

For example, a Soviet gun showing 159mm here would be published as ~175mm in Soviet documents, and a German gun showing 120mm would be published as 120mm in German documents. The 159mm figure is directly comparable to the German 120mm - the Soviet gun really was more powerful.

National Testing Standards
German:	1.00? - Complete penetration, fuze functions (strictest)
British:	1.02? - Complete penetration
American:	1.05? - 50% of shell mass through plate
Soviet:	1.10? - 75% of shell mass through plate
All database figures are normalized to German standard for direct comparison. Multiply by the factor above to see original national test figures.

Hit probability is based on a static 2 x 2.4 metre panel at 0 degrees(vertical) at the range specified.

The data that has been used to create these records has come from Wikipedia, The Lone Sentry, The Bundes Archive and numerous books and websites that have provided the detailed information that has not been available anywhere else. The information we use to calculate the penetration tables, flight times and the hit probability comes from the Gun Calibre, the Shell Mass(Kg) and the muzzle velocity, plus range reductions to allow for gravity and wind resistance. This calculation originally came from a pre-war Krupp calculation which has been modified, and seems to fit the actual test results.