If one single round was missing there would be no pressure to load the next, I imagine.
Pressure from the feed, or action of the gun. Different questions.
Did the gun then stop firing, whether a 30 calibre in Tunisia, an MG42 in Cassino or an M60 in Hue?
I don't think any of those cases can HAVE a round missing in the belt. So kind of a moot question.
There are two components to the feed system to be understood in order to figure out the answer.
First is: How does the cycling of the gun work?
Second is: How does the ammo feed work?
These questions will have different answers in different guns, and so you will see different results.
For most machine guns, the cycling action is either gas or recoil operation. Sub-machine guns (or machine pistols), with smaller lighter cartridges often rely on blowback as their mechanism. All of these three mechanisms rely upon a round being fired to generate the force that will be used in the mechanism to extract the empty cartridge, re-cock the striker, and chamber (load) the next round.
If, for any reason, a round fails to fire, then the next round will not be fed in by the mechanism, and the gun will stop firing. Doesn't matter what the feed mechanism (the answer to the second question) is. A dud round, a missing round, or a mis-feed of any sort will stop the automatic fire of the gun. Manual cycling of the action will then be required to re-start automatic firing.
This was not terribly uncommon. You will often see machine gunners working the bolts of their guns (pulling and releasing) to manually work the action and feed the next round when the gun stops shooting.
About the only exception to this are chain-guns (like the US 25mm auto cannon in the Bradley and LAV light vehicles) and rotary ("gatling") guns, like the hand-cranked Gatling guns of the late 1800s and the modern Vulcan electric rotary guns in most current US gun-armed aircraft. In those cases, the mechanism of cycling the gun uses an external source of power, and so the gun continues cycling even if one round fails to fire.
The ammo feed is a separate question. Most magazine mechanisms use a push plate under tension from a spring to push the rounds into position to be fed by the gun mechanism. Many machine guns use belt-feed, which relies on the rounds being pulled into the mechanism by the belt which connects them all.
Cloth belts retained their integrity even if a round was missing. You still have a belt even if it has an empty sleeve in it. So it was possible to have a gap in the ammo in the belt, requiring a manual cycling of the gun to get it firing again. Disintegrating metal belts don't work this way. Each link is spring-loaded against the cartridge case. Remove the cartridge and the link separates from the rest of the belt and falls to the ground as a bit of waist metal. The only way to have a "missing round" in the belt is to have an empty cartridge or dud round in the belt. There can be no empty space in the belt, as there is no way to connect a one cartridge in a belt to another cartridge in a belt over, through or around an empty space.
Spring-loaded magazines are also not 100% reliable feeds. It is possible for the action of the gun to miss the round at the top of the magazine. In the case of a gas, recoil, or blowback operated gun this will again cause a mis-fire, and the action will need to be manually cycled.
The original Gatling guns were magazine fed, but without a spring. Instead they relied on gravity to cause the rounds in the magazine (above the gun) to fall into position as the gun cycled. This was not a particularly reliable form of feed. But the hand-crank action of the Gatling gun kept it firing despite most mis-feeds, so in the end it was a reasonably reliable gun, even if it was kind of like "POW POW POW click POW POW click click POW POW POW" rather than the "Ratatatatat" we expect from a modern machine gun.
-Mark
(aka: Mk 1)
is excited to paint something new.
