Recoilless rifles were first introduced at the end of World War II and started to see service during the Korean War. However, the recoilless rifle in service during the Korean War, the M27 (a 105mm weapon), was too heavy and impractical to be used as a tank destroyer. 

The M40 Recoilless Rifle, first developed in 1950, is a 105mm anti-tank weapon developed in the United States that saw much more success than the M27 Recoilless Rifle. 

One might wonder, then, why the M40 is sometimes referred to as the M40 106mm Recoilless Rifle when its bore is, in fact, 105mm and not 106. It is given this 106 mm designation largely to distinguish it from the M27 mentioned above that did not enjoy the same success. It’s also with noting that the cartridge cases accepted by the two guns are incompatible with one another. 

By contrast, the M40 was capable of firing 105mm rounds intended as both anti-tank and anti-tank ordnances. In the United States, the M40 was predominantly used with four different rounds, two of which were intended for use as anti-tank rounds and two of which were used as anti-personnel rounds. 

The United States M494 and M581 rounds were both intended as anti-personnel ordnance with an effective range of 300 meters. The U.S. also produced two anti-tank rounds, the M346A1 HEP-T (High Explosive Plastic) and M344A1 HEAT (High Explosive Anti Tank with armor-piercing capabilities) rounds. 

The M40 saw use in the hands of American troops through the Vietnam War and, due to its significant improvements over the design of the M27, it remained in service long after. In fact, there are still some parts of the world today where the M40 106mm still sees use. 

If you’d like to learn more about the development of the M40 or its history of service, please get in touch with our firearms experts or reach out to us directly at 610-250-3960. You can also find a line of M40 accessories right here on this page.