Briefly, "Failure to Feed" is defined as when the weapon fails to feed a cartridge into the firing chamber for some reason. In a semi-automatic or an automatic weapon, this means that the cartridge does not properly travel from the magazine to the chamber and the slide remains partially open. When this happens, the weapon is said to be "out of battery".
There are several reasons why a firearm could fail to feed a cartridge:
- Dirt: Accumulation of dirt in the firing chamber, bolt or bolt carrier can cause the cartridge not to sit properly inside the firing chamber.
- Damaged magazine: If the magazine has dents, bulges or damaged lips, these may cause the cartridge to be misaligned as it is being fed into the chamber. A weak magazine spring may also cause failures to feed.
- Improperly loaded magazine: The magazine could be in good shape, but it may not be pushed all the way into the firearm, which may cause the cartridges to not enter the chamber correctly.
- Damaged cartridge: Sometimes the cartridge may have dents or bulges in it which could cause a failure to feed, as the slide may not pick it up correctly, or it may not fit into the chamber tightly because of dents or bulges.
- Riding the slide: This is when the user holds the slide as it is moving forward and impedes its speed. When this happens, the slide may not have enough momentum to properly seat the cartridge in the chamber. The user should pull the slide back as far as it will go and then let it go and let the recoil spring do the job of loading the next cartridge.
In most cases, a failure to feed can be easily fixed. For instance, dirt in a firearm can generally be cleaned fairly easily, an improperly loaded magazine can be pushed into place, damaged cartridges can be removed from the magazine and discarded etc. All these are easy for the average user to do and not expensive at all. In other cases (e.g.) damaged magazine or weak magazine springs, the magazine may need to be replaced, or it may need to be sent to a gunsmith for repair. The cost of replacing a magazine is usually affordable (e.g. about $20-$30 or so) in most cases.