In conventional designs, casings are typically ejected by the force of the gases used to propel the round, possibly being assisted by gravity to help with the ejection path. Linked belts tend to break, twist, and/or bind such that the gun cannot load the next round. Typical guns use belts of ammo chained together as in the classic 0.50 cal M2.

The problem is the that most gun designs were engineered on the ground with a simple level 1-g load.Īir combat really tests an engineers ability to feed ammo and eject casings rapidly no matter what the environment. Low, no, or negative g-loads can cause problems as well. High-g turns can cause problems with feed/extraction mechanisms. Typically, jams are caused by firing the guns while under unusual g-loads. Why else would the US stick with one design for so long when other versions are available in 25mm (AV-8B Harrier) and 30mm (4-barrel version of GAU-8 used in gunpods for F-15E)? If the purpose of the gun is air-to-air, the modern version of the 20mm round is more than adequate. Of course, some would say the caliber is too small compared to many aircraft that have 23mm, 27mm, or 30mm cannon. While always quoted as having selectable 3000 or 6000 rounds per minute, the fact is over short bursts, the 6-barrels do not instantly spin up from 0 rpm to 500 or 1000 rpm.īut even if the effective rate of fire isn't much better than most quad-mounted single barrel 20mm cannon, as long as the feed mechanism doesn't jam, the gun is self-clearing when hydraulically or electically powered. Though I bet TK hasn't modeled the spool-up time that greatly reduces the effective rate of fire. Without even checking the gun data, I am sure TK has modeled this advantage. The 20mm Vulcan rotary cannon has many disadvantages, but in most versions of it, reliability is not one of them. There is a reason the 'Last Gunfighter' got most of its kills with AIM-9s!

Some weapons on some aircraft were notorious for jamming, notably the F-8 Crusader's 20mm cannons. If you are using spray-n-pray, you will jam almost any gun in the game very quickly. Take as few shots as possible and use short controlled well-aimed bursts to reduce the likelyhood of a jam. Some gun installations are more likely to jam than others.

High speed gun jam