M7 Self Propelled:

Royal Armored Corps Tank Museum

Aberdeen Tank Museum

Based on experience with mounting 105 mm howitzers on half-tracks the US Army wanted a fully tracked version. Used a modified M3 Medium or M4 Medium tank chassis. Upper hull was modified to hold a 105 mm howitzer in the front. A drum-like cupola was added on the right side to hold a .50 cal MG.

Two prototypes were built and designated T32.¹ Had an open superstructure with a M1A2 105 mm howitzer installed to the right of the center. It was accepted and standardized as the M7 HMC in February 1942. Production started in April 1942.¹

Was declared Substitute Standard in January 1945.

Production models had modified shields and a cupola for the AA MG. The 105 mm gun could fire a 33 lb HE shell at a velocity of 1,550 ft/sec, and a range of 11,500 yards.⁶

First used by the US Army in 1942.¹

The Marines would use them in an armored personnel carrier roll. It could carry up to 13 marines up to the front lines. The Marines used them extensively on Okinawa.

Used M3 Medium chassis.¹ Late models had M4 type bogies with trailing return rollers.¹ Some had cast one part nose.¹ American Locomotive produced vehicles. The upper parts of the side and rear armor are hinged and held in place by locked pins. There were grip handles on the outside of the armor that were used as ladders.

The driver had vision through a removable windshield and a protoscope.

M7B1:

Patton Museum in Ft Knox, Kentucky

Chris Bobo

Standardized in September 1943. Declared Substitute Standard in January 1945.

Used chassis of M4A3 and Ford GAA engine. Cast nose. Pressed Steel produced vehicles. There were hinged plates on the side to protect the tips of the ammunition (stored vertically) from being hit by arms fire.¹ Late models had lower hull made out of soft steel because of economy measures.¹ Federal Welder built 127 of both types.

M37:

Aberdeen Tank Museum

Some felt that the M7 was too heavy so a M24 chassis was used.¹ Standardized in November 1944.¹ 448 were ordered.¹

Based on the M24 chassis.¹ Had drive sprocket in rear with individual torsion bar suspension. Had larger working space and storage space for ammunition than M7.¹ It was powered by twin Cadillac engines. It had Hydra-Matic transmissions.

The 105 mm gun fired a 33 lb HE shell at a range of 12,200 yards.⁶

British Service:

Initially ordered 2,500 and this was later increased by 3,000.¹ The MG gun position reminded the British soldiers of a church pulpit and was called the "Priest."^1,6

Priest:

In September 1942, 90 M7s were sent to 8th Army and was available for Battle of Alamein.¹ Were used in Normandy but were soon replaced by Sextons. Could have a No. 19 wireless radio installed if 24 rounds of ammunition were removed.

Used by the 5th Royal Horse Artillery at the Battle of Alamein.⁶

Priest Kangaroo:

102 were converted from October 1944 - April 1945.  Carried 20 infantrymen plus crew of 2.

Priest OP:

Removed gun and added communications gear.

	M7	M7B1	M37
Crew	Commander, driver, gun crew (5).2,4 53 71,2,4,6	Commander, driver, gun crew (5).2 72	Commander, driver, gun crew (5) 71,6
Physical Characteristics
Weight	50,634 lb2,3 19.9 tons4, 22.6 tons1, 28.5 tons6 22,997 kg1,3	50,000 lb2	40,000 lb 20.5 tons1, 23 ton6 20,865 kg1
Length w/gun	19' 9"1,2,3, 20.4'6 6 m1, 6.02 m3,4	20' 3.75"2	18'1,6, 18' 2" 5.48 m1
Length w/o gun
Height	8' 4"1,2,3, 9.7'6 2.5 m1, 2.54 m3,4	8' 4"2	7' 4", 7.9'6, 7' 11"1 2.41 m1
Width	9' 5.25"2,3, 9' 6"1,6 2.87 m4, 2.88 m3, 2.9 m1	9' 5.25"2	9' 8"1, 9.8'6, 9' 11" 2.99 m1
Width over tracks
Ground clearance	1' 5", 17.1"6	1' 5"	1' 5", 18.4"6
Ground contact length	147"6	147"	123"6, 124"
Ground pressure	10.4 psi6	10.4 psi	10.1 psi, 11.7 psi6
Turret ring diameter
Armament
Main	105 mm howitzer3 105 mm M1 or M2 howitzer1 105 mm howitzer M1A2, M2, or M2A12 105 mm M1A2 or M2 howitzer4 105 mm howitzer M2A1, L/246	105 mm howitzer M1A2, M2, or M2A12	105 mm M4 in M5 mount, 105 mm M4 howitzer1 105 mm howitzer M46
Secondary
MG	.50 cal MG, AA2,4 12.7 mm (.50 cal)3 .50 cal M2 MG, AA6	.50 cal AA2	12.7 mm (.50 cal) MG .50 cal M2 MG6
Side arms	3: .45 Submachine guns	3: .45 Submachine guns	.45 Submachine gun, 6: .30 carbines Grenades
Quantity
Main	692,4,6	692	90, 1266
Secondary
MG	3002,6	3002	500, 9906
Side arms	.45: 1,620	.45: 1,620	.45: 600 Grenades: 8
Armor Thickness (mm)	122, 622 (Actual thickness of armor at horizontal) Front: 1"6, 124 Side: 0.5"6, 124	122, 622 (Actual thickness of armor at horizontal)	(Actual thickness of armor at horizontal) Front: 0.5"6 Side: 0.5"6
Hull Front, Upper	0.5" (0.5")	0.5" (0.5")	0.5" (1.25")
Hull Front, Lower	2-4.25" (2-4.5")	2-4.25" (2-4.5")	0.5" (7/8")
Hull Sides, Upper	0.5" (0.5")	0.5" (0.5")	0.5" (0.5")
Hull Sides, Lower	1.5" (1.5")	1.5" (1.5")	0.5" (0.5")
Hull Rear	0.5-1.5" (0.5-1.5")	0.5-1.5" (0.5-1.5")	0.5" (7/8")
Hull Top
Hull Bottom	0.5-1" (0.5"-1")	0.5-1" (0.5"-1")	3/8-0.5" (3/8-0.5")
Turret Front			Gun mount shield: 0.5" (0.5")
Turret Sides
Turret Rear
Turret Top
Engine (Make / Model)	Continental R-975 C11,6 Continental R-9752,4 Continental3	Ford GAA V81,2	2: Cadillac 44T241 2: Cadillac6
Bore / stroke	4 cycles6
Cooling	Air6		Water6
Cylinders	93, R-96		V-86
Capacity
Net HP	2204, 350@2,400 rpm6, 3753		110@3,400 rpm6
Power to weight ratio
Compression ratio
Transmission (Type)	Synchromesh6 5 forward 1 reverse6	5 forward 1 reverse	Hydramatic6, Hydra-Matic 2 forward, 1 reverse6 8 forward 4 reverse
Steering	Controlled differential6		Controlled differential6
Steering ratio
Starter	Electric6		Electric6
Electrical steering	24-volt6		24-volt6
Ignition	Magneto6		Distributor6
Fuel (Type)	Gasoline6		Gasoline6
Octane
Quantity	179 gallons6	179 gallons	110 gallons6, 115 gallons
Road consumption
Cross country consumption	0.5 mpg6		0.9 mpg6
Performance
Traverse	12.25° left and 25.5° right6, 15° left and 30° right1,2,4	15° left and 30° right2	22.5° each6, 45° up1
Max speed	24 mph1,6, 25 mph, 26 mph3 39 kph1, 40 kph4, 41.8 kph3	25 mph	30 mph1, 35 mph6 48 kph1
Cross country speed	15 mph2	15 mph2	5-25 mph6, 15 mph
Road radius	120 miles1, 125 miles3 193 km1, 201 km3		100 miles1, 160 km1 85-125 miles
Cross country radius	85 miles6		100 miles6
Turning radius	62'	62'	40'
Elevation limits	+35° to -5°1,2,4,6	+35° to -5°2	+45° to -10°6
Fording depth	4'2,3,6 1.219 m3	3'2	42"6
Trench crossing	7' 6"2,6	7' 6"2	7', 9'6
Vertical obstacle	2'2,6	2'2	36"6, 3' 8"
Climbing ability	31° (60%) slope6		31° (60%) slope6
Suspension (Type)	Vertical volute2,6	Vertical volute.2	Vertical volute Torsion bar6
Wheels each side	6, 3 bogies - 2 wheels each6	6	56, 6
Return rollers each side	36	3	3, 46
Tracks (Type)	Dry pin, double pin per shoe, rubber bushed cleat6		Steel block, with center guide, rubber bushings6
Length
Width	1' 4.5"2, 16.6"6	1' 4.5"2	16"6, 1' 4.5"
Diameter
Number of links	796		806
Pitch	6"6		5.5"6
Tires
Track centers/tread	6.9'6, 6' 11"2	6' 11"2	6' 11", 8'6
Production	4/42-12/42: 2,028 American Locomotive Co, Federal Machine & Welder Co., Pressed Steel Car Co.6	3/44-2/45: 826	3161 Cadillac (Detroit), Massey-Harris (Milwaukee): 3165 Cadillac6

Sources:

1. The Encyclopedia of Tanks and Armored Fighting Vehicles - The Comprehensive Guide to Over 900 Armored Fighting Vehicles From 1915 to the Present Day, General Editor: Christopher F. Foss, 2002
2. British and American Tanks of World War Two, The Complete Illustrated History of British, American, and Commonwealth Tanks 1933-1945, Peter Chamberlain and Chris Ellis, 1969
3. The Encyclopedia of Weapons of World War II, Chris Bishop, 1998
4. Jane's World War II Tanks and Fighting Vehicles The Complete Guide, Leland Ness, 2002
5. Tanks of World War II, Duncan Crow, 1979
6. Tank Data, Aberdeen Proving Grounds Series, 1968?

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