Introduction to M197 cannon

M197 cannon

The M197 cannon, officially called the M197 automatic cannon, is not widely used, but it is very common, because this 20mm three-barreled Gatling cannon is The main weapon of the AH-1 Cobra series armed helicopters. The reason for developing the M197 was that the experience of the Vietnam War showed that the power and range of the 7.62mm machine gun used on the gunship were insufficient. Therefore, in 1968, General Electric Company reduced the gun barrels to 3 based on the M61, and the maximum rate of fire was also reduced to A quarter of the original size so that it can be used on light aircraft or helicopters. The M197 cannon uses M61's M50 series and PGU series 20mm shells.

On the AH-1 helicopter, the M197 cannon is part of the M97 weapon system, replacing the M28 armed system and XM35 armed system originally used on the AH-1 helicopter. The first one used on the AH-1S was the M97E1, which was later improved to the M97E2. Then it was improved from the AH-1F type to the M97A3 and M97A4, and the M97A4 has been used to this day.

On the AH-1 helicopter, it can carry 750 rounds of 20mm artillery shells. The M197 cannon in the M97 system needs to be matched with the M89 or M89E1 delinking mechanism. This is mainly because the ammunition chain loading will be more convenient and faster, and it is more suitable for replenishing ammunition for helicopters under simple field conditions. The cannon is mounted on the A/A49E-7 turret and can be rotated 200 degrees horizontally and 60 degrees vertically. The theoretical rate of fire of the M97 is 730 rounds per minute, but it can be adjusted to a maximum of 2,000 to 3,000 rounds per minute. The standard firing pattern is a long burst of 100 rounds, with a few seconds of cooldown between bursts.

The GPU-2A cannon pod can also be used on the AH-1 helicopter. An M197 cannon is installed in the pod and carries 300 rounds of artillery shells. GPU-2/A has a total length of 3.25m, a maximum diameter of 482mm, and a total weight of 265kg when fully loaded with M50 live ammunition. It adopts chainless ammunition supply and has a theoretical firing rate of 750 or 1500 rounds per minute. The GPU-2/A can also be used on other vehicles, but the more common one is hung on the belly of the OV-10.

Currently, the M197 cannon is still used on the latest AH-1W and AH-1Z armed helicopters. Although the rotary cannon is very reliable in theory, it is said that US Marine Corps pilots have been reporting this problem. The weapon system has an astonishing jamming rate (said to be greater than 30%). Although the US Marine Corps and manufacturers are aware of this problem, no specific improvement projects have been incorporated into the AH-1Z program. At the same time, they hope to reduce the chance of such failures by training service personnel.