DEVELOPMENT OF AN advanced gun has been proposed for the US/UK Joint Strike Fighter (JSF) because of concerns over the weight, cost and effectiveness of the current M61 20mm cannon. The four services planning to buy the JSF have yet to agree whether it should have an internal gun.

The US Air Force supports development of an advanced gun, at a cost of about $60 million. This is because of the "unique capabilities" offered by increased-calibre caseless ammunition with improved propellants, when coupled with advanced avionics, says Brig Gen Bruce Carlson, director of global-power programmes.

A 25mm gun would provide the capability to attack an aircraft head-on within missile minimum launch-range, as well as to penetrate ground targets at stand-off ranges of 2,500-3,000m (8,200-9,800ft), he says.

The US Marine Corps is prepared to follow the USAF's lead, but it is concerned about the weight impact of an internal gun on its short-take-off/vertical-landing variant of the JSF. The service would prefer a "clip-on" gun, similar to the 25mm gun pods on its McDonnell Douglas AV-8Bs. The UK's Royal Navy is likely to follow the USMC.

Source: Flight International