In a Failure to Eject type malfunction, the old cartridge shell is properly extracted from the chamber after it is fired, but due to some reason, it doesn't get ejected out of the ejection port and stays in the gun partly. Because of this, the slide cannot close and the gun gets jammed. We've actually already studied one type of Failure to Eject last month: The Stovepipe Jam.
A pistol jammed by a stove pipe jam (A Failure to Eject type malfunction).
Click on the image to enlarge.
As can be seen in the picture above, the empty cartridge case was not fully ejected out of the firearm and got caught in the slide, thus preventing it from closing fully and therefore leaving the pistol jammed.
As far as the reasons why this happens, the big reasons are:
- Dirt: Buildup of dirt or corrosion near the magazine spring, return spring or extractor can cause it to fail to eject.
- Limp wristing of weapon: We already studied the subject of limp wristing a couple of months ago. By not holding the firearm strongly enough and not offering enough resistance and rigidity to the recoil forces of the firearm, the firing action may not complete its cycle properly and hence a jam occurs. This is more commonly seen when using pistols and is usually the #1 cause of failure to eject.
- Defective ammunition: The propellant in the cartridge case may have degraded sufficiently due to age, or the cartridge may not have been filled with enough propellant. Either way, the burning propellant doesn't generate enough power to cycle the action properly and so the cartridge doesn't get fully ejected by the time the slide returns back.
- Faulty ejection mechanism: Either the return spring of the slide may be too strong or the magazine spring that ejects the old cartridge is too weak. In either case, the slide moves back and then gets pushed forward and starts to close before the old case is ejected. Therefore, the old case gets caught before it has a chance to fully leave the firearm. The ejector may also be damaged (this is the piece that is near the back of the empty cartridge's movement, which pushes the empty cartridge out towards the ejection port), which may cause it to fail to push the shell out.
- Spin back The old cartridge case does get ejected, but it hits something on the way out (e.g. the ammunition belt, or the drum, or the side of the ejection port) that causes it to spin back into the ejection port instead of going out of the weapon. Some rifles are more susceptible to this than others: e.g. the Stoner 63A, which was used by SEALs in Vietnam, occasionally suffered this when configured with a snail-drum magazine which fed from the left hand side. It did not exhibit this issue when configured with a box magazine fed from the right hand side.
Remedying this problem in the field is fairly easy as the stuck empty cartridge is usually easy to remove without using any tools. The primary cause of this problem in handguns is because of limp-wristing. However, if the problem continues to happen, then the extractor, ejection spring or return spring (or more than one of the above) may need to be replaced.