M7 Self Propelled:

United States' M7 Self Propelled Gun
Royal Armored Corps Tank Museum


Aberdeen Tank Museum

USA's M7

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
United States M7B1 Self Propelled Howitzer
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

USA's M37

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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