155mm Self Propelled Gun M53, an American Boom Stick

[Conraire 5,723]

Hello All, Today I'd like to propose the addition of the 155mm Self-Propelled gun M53.

Spoiler

Background

The M53 is an American Self Propelled Artillery Gun, which was developed and prototyped by mid 1952, prototype designation Gun 155mm SP T97, and produced until mid 1955.  It came armed with the 155mm T80/M46 Heavy Artillery gun, and carried a load of 20 complete rounds of ammunition in the casemate.  Due to limited funding, to keep production simplified, and to ensure maximum interchangeability, it used many features and components from other vehicles that were developed around the same time.  Such as the tracks and running gear from the M46 and M47 tanks, the now common AV-1790-5 engine with the CD-850-4 transmission power pack combo, and eventually the Steering wheel system from the M48.  After 1956, the Army converted all of their M53's to the M55 configuration.  However, the Marines kept using the M53 through Vietnam, eventually being replaced by the 8in M55, and then the lighter M110.

 

Its place in the Game

Going by its capabilities and the fact that it was produced through the mid 1950's.  I see it as being pretty capable Korean to Vietnam War Era vehicle.  As such, I would suggest an approximate battle rating range of 7.0 to 8.0.  We already have similar vehicles in game, such as the Japanese Type 75 SPH.  And the US tree, has long been missing a heavy direct fire self-propelled artillery gun, especially in the Tier 5 area..  The M53's main gun with the capability to fire a high pen APHE round, and proximity fuzed HE rounds, would make it quite deadly against most vehicles.  Though the relatively high silhouette of the vehicle, may make it difficult to hide in cover.

 

Vehicle Specifications

Dimensions

• Crew: 6, Commander(turret right), Gunner(turret right front), 3x Loader/Cannoneers (Turret), Driver(Turret left front)
• Weight(combat): 98,700lbs (44,769kg) 44.7Tons
• Length: 27ft 1in (791cm) Hull, 31ft 7in (972cm) Gun forward
• Height: 11ft 8in (347cm) Over AAMG
• Width: 11ft 8in (358.1cm) Over fenders
• Turret Ring Dia: 59.5in (151cm) Inside
• Ground Clearance: 18.5in (47cm)
• Ground Pressure: 11.8psi

Armament

• Primary Armament: 155mm Gun (T80)M46, M86 Mount, Casemate Turret (20rnds)
• Rate of Fire(max): 2 rounds/min
• Traverse: 60° @ 10°/sec (Manual and Hydraulic)
• Elevation: +65° to -5° @ 7.5°/sec (Hydraulic)
• Stabilizer: None
• Secondary 1: .50cal M2HB MG, flexible ring Mount on cupola, 360° (Manual) (900rnds)

Armor

• Assembly: Welded

• Hull: Rolled Homogeneous Steel
• Armor Hull: Upper Front (19mm @ 10°), Lower Front (19mm @ 57°), Sides (12.7mm @ 0°), Rear (12.7mm @ 0°), Top (12.7mm @ 90°), Floor (19mm @ 90°)

• Turret: Rolled Homogeneous Steel
• Armor Turret: Gun shield (12.7mm @ round), Front (12.7mm @ 20.5°), Sides (12.7mm @ 0°), Rear (12.7mm @ 0°), Top  (12.7mm @ 90° )

Performance/Automotive

• Engine: Continental AV-1790-5B or 7B, Gasoline, 12cyl
• Net HP: 704hp @ 2800rpm
• Gross HP: 810hp @ 2800rpm
• Net Torque: 1440ft-lb @ 2000rpm
• Gross Torque: 1610ft-lb @ 2200rpm
• Transmission: GM CD-850-4 or 4B, 2 Ranges Forward, 1 Reverse
• Suspension: Torsion Bar
• Steering: Mechanical, Wobble stick, or steering wheel
• Brakes: Multiple Disc
• Speed: Road Max High Range: 30mph (48km/h), Low Range: 12mph (19km/h), Reverse: 12mph (19km/h)
• Max Grade: 60%
• Min Turn Circle: Pivot

 

Armament information and Ammunition

The 155mm Self-Propelled gun M53 used the 155mm (T80) M46 Gun.  According the Hunnicutt's this gun has a bore length of 45calibers and had a basic ammunition load of 20 rounds.  Firing M101 HE shell with either normal or super charge.  M104 WP Smoke shells, or M104 HD Gas shells (these wouldnt apply to the game).  The gun, at least according to Hunnicutt's could fire 1rnd/min.  However, according to FM 6-40 Field Artillery, Gunnery, April 1957.  The gun could fire at a rate of 2rnd/min. 

Spoiler

 

FM 6-40 as well as FM 6-93, also list the following ammunition as usable by the (T80) M46 Gun.  

Spoiler

 

155mm M101 Deep cavity HE Shell, with either Point detonating, Timed, or VT proximity Fuze

155mm M112 AP Shell, base detonating fuze

155mm M104 WP Smoke Shell, 

155mm M118A1 Illumination shell Timed fuze.

 

Ammunition Specifications

 

M101 HE Shell

Weight: 95.73lbs (43.42kg)

Muzzle Velocity(super Charge): 2800ft/s (853m/s)

Burst Charge: 15.48lbs (7.021kg) TNT

Fuze: Point Detonating

 

M101 HE Shell, Deep Cavity

Weight: 95.10lbs (43.14kg)

Muzzle Velocity(super Charge): 2800ft/s (853m/s)

Burst Charge: 14.61-14.91lbs (6.62-6.76kg) TNT

Fuze: Point Detonating, Timed Mechanical, or VT proximity

 

M112 APBC-HE Shell

Weight: 100lbs (45.36kg)

Muzzle Velocity(super Charge): 2745ft/s (837m/s)

Burst Charge: 1.44lbs (653g) Exp. D

Fuze: Base Detonating

Penetration RHA (Wiki calc): 246mm @ Vertical 10m Range

 

M104 WP Smoke Shell 

Weight: 97.90lbs (44.4kg)

Muzzle Velocity(super Charge): 2800ft/s (853m/s)

Burst Charge: 15.6lbs (7.076kg) WP

Fuze: Point Detonating

 

Spoiler

 

References used

 

Patton, A history of the American Main Battle Tank, by RP Hunnicutt.

FM 6-40 Field Artillery Gunnery April 1957

FM 6-93 155mm Assault Gun M53, and 8-inch Howitzer M55, Self Propelled, Field Manual

TM 9-1300-203 Ammunition for Anti Aircraft, Tank, Anti Tank, and Field Artillery Weapons, August 1960

TM 9-1901 Artillery Ammunition June 1944

TM 43-0001-28 Army Ammunition Datasheets, Artillery Ammunition

Correspondence Thru 1956 - Gun, 155mm, SP, T97 - Courtesy of Harold Biondo's Patreon Page.

http://afvdb.50megs.com/usa/155mmspgm53.html

https://www.tanks-encyclopedia.com/coldwar/US/M55-Self-Propelled-Howitzer.php (Third Image is from here)

Edited July 18, 2022 by Conraire
Revisions to Armor and other parts

[kurururocks 210]

Open for discussion

[Milocat 4,848]

+1 as an American derp cannon.

[Conraire 5,723]

Made some small revisions to the armor layout based on more accurate information.  Originally it was based on data from the 50megs website, now its based on the correspondence archival documents on the T97.  Also updated the vehicle combat weight, and max speeds and reverse speed based on said data.  That will most likely stand until I can find a copy of the TM 9-7212 manual for the T97/M53.  

[hienapunk 1,064]

America could really put together an entire line of pretty vicious self propelled howitzers and rocket artillery.

[ᅟᅟ 28]

Where did the suggestions for the M55 go?

[Conraire 5,723]

5 minutes ago, AnD_O said:

Where did the suggestions for the M55 go?

 

The old suggestion that had both got archived when the suggestion mods cleaned up the section, due to not complying with updated rules..  I just haven't had the time to make a new one for the M55 yet, unless someone else wants to.

[G1label 143]

+1 this would be nice for between the m36b2 and t95 at br 5.7-6.0 or so. Should be able to pop open everything you see with this gun.