120mm Rheinmetall Rh-120

M256

Overview

Strv 122

Swedish Strv 122 main battle tank firing its 120mm main gun.
Source: US Army - © Public domain

Origin

Germany

Type

Cannon

Entered service

1979 for Rh-120-44
2001 for Rh-120-55
2018 for L/55A1

Status

In service

Development

1970's

Developer

Germany - Rheinmetall

Production

Mid 1970's - present

Producer

Germany - Rheinmetall
United States - Watervliet Arsenal
Japan - Japan Steel Works

Number produced

Over 10.000

Designations

M256 (US production model)
KM256 (South Korean service)

Description

Introduction

The Rh-120 is a late Cold War era smoothbore cannon of German origin. It was developed to arm the new Leopard 2 main battle tank. NATO thought that the highly successful 105mm L7 used on the Leopard 1 was probably not future proof considering Soviet tank development. Over time the design of the gun and its range of ammunition was continuously improved. This makes current iterations rank among the most powerful tank armament in service today.

Design

The Rh-120 was developed around a new range of 120mm ammunition, with emphasis on an APFSDS rounds. Therefore it is a smoohtbore cannon. The gun is loaded manually using single piece ammunition, of which the majority of the shell casing is combustible. The barrel is autofrettaged for increased barrel life and features a fume extractor and a muzzle reference device.

Firepower

Maximum range of the Rh-120 is about 3 km with APFSDS ammunition. The rate of fire depends on the loader. 10 rpm is quoted, with that rate dropping off as fatigue increases and ready rounds are spent.

Variants

Rh-120-44

Original 120mm 44-caliber production model introduced on the German Leopard 2 main battle tank.

Rh-120-55

55-caliber variant developed under the KWS I program to upgrade the combat effectiveness of the Leopard 2 main battle tank.

Rh-120-55 A1

Similar to earlier L/55 model, but allows for even higher pressure. Also known as L/55A1. Entered service in 2018.

M256

US production variant for use in the M1A1 and M1A2 versions of the M1 Abrams main battle tank.

JSW 120mm

Japanese production version for use in the Type 90 main battle tank. Fed by bustle mounted automatic loader.

Details

Facts Rh-120-44 Rh-120-55

General

Origin

Germany

Type

Smoothbore cannon

Caliber

Caliber

120mm

Ammunition type

120x570mm, fixed case

Feed system

Manual loading

Barrel length

5.28 m

Rifling

Smoothbore

Fume extractor

Yes

Muzzle velocity

1.640 m/s with DM33 APFSDS-T

Operation

Rate of fire

About 10 rpm

Recoil force

Up to 600 kN

Dimensions

Weight

1.190 kg gun only

3.780 kg including mount

Media

Leopard 2A6

Portugese army Leopard 2A6 main battle tank in the field.

Source: Allied Joint Force Command Brunssum

Leopard 2A4

Austrian Leopard 2A4 main battle tank firing its 120mm main gun.

Source: Bundesheer

Leopard 2A4

Norwegian Leopard 2A4 main battle tank firing its 120mm main gun.

Source: US Army

Type 90

Left side view of Type 90 main battle tank.

Source: Unknown author

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Platforms with Rh-120

Leopard 2A4

The Rh-120-44 was introduced on the Leopard 2 main battle tank, entering service in 1979.

Leopard 2A5

The Leopard 2A5 is an upgrade over the earlier Leopard 2 with distinctive new armor package. The L/44 cannon was retained, since the L/55 was still under development.

Leopard 2A6

The Leopard 2A6 introduced the 55-caliber variant of the 120mm smoothbore cannon, entering service in 2001.

Leopard 2A7+

The Leopard 2A7+ is a highly modified Leopard 2A6 featuring various urban combat improvements. It seems that the first L/55A1 entered service on this variant of the Leopard 2.

Type 90

The Japanese Type 90 main battle tank is equipped with a modified L/44 cannon produced under license in Japan.