Firearm Malfunctions: Stovepipe Jam

In the next few posts, we will study some cases of malfunctions in firearms. The first one we will study is the stovepipe jam.

A typical stovepipe jam. Click on image to enlarge.

Note that in the above image, an empty cartridge case is stuck in the ejection port at the top of the pistol.  This is an example of a stovepipe jam. The reason that this is called a stovepipe jam is because the empty cartridge case resembles the chimney pipe of an old fashioned cooking stove.

A stovepipe jam usually occurs in semi-automatic or fully-automatic firearms and is a failure-to-eject malfunction (i.e.) the cartridge that was just fired did not get ejected from the firearm properly and the cartridge case is partially stuck in the ejection port. This means the weapon cannot load the next cartridge into the chamber properly and will not fire.

There are four major causes of stovepipe jams:

1. Limp wristing the weapon: We already studied the subject of limp wristing a month 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.
2. Old or bad ammunition: The propellant in the cartridge case may have degraded sufficiently due to age, or the case 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.
3. Bad ejection mechanism: Either the return spring of the slide may be too strong or the ejector 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.
4. 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.

Stovepipe jams are relatively easy to clear. We will study how to clear firearms at the end of this series. For now, we will continue studying other types of malfunctions in the following posts.

What is Limp Wristing?

We sometimes hear the term "limp-wrist" in firearms terminology. So what is it? Is it a good thing or a bad thing? What should we do to counter it? This post aims to answer all these questions.

In the various posts in the past, where we dealt with semi-automatic and automatic firearms, we studied several different actions: recoil operated action, gas operated action, blowback action etc. The previous links can serve as a refresher course for the uninitiated reader of the basics of these various mechanisms. The one thing in common is that the firearm uses a force (either from recoil, gas pressure etc.) to push back the bolt or slide of the firearm, which then removes the old cartridge and cocks the weapon on its way back. It also compresses a spring on the way back and this spring pushes the slide or bolt forward, whereupon it readies itself to fire the next round.

Now, imagine what happens if there isn't adequate resistance offered to the firearm's frame during the backward movement of the bolt or slide (i.e.) if the frame of the firearm is allowed to move backwards with the bolt or slide. Then what will happen is that the operating cycle may not properly complete and the old round may not get ejected in time and the next round may get jammed, rendering the firearm temporarily inoperable. There are a few reasons for this phenomenon to occur, but one of the common reasons is because the user had a loose grip on the firearm, which is why it is called as "limp wristing".

Limp wristing isn't confined to pistols alone. For instance, a rifle or shotgun may also have problems operating properly, if the user doesn't provide a firm shoulder to  rest the butt on. Model of firearm also  has a lot to do with it, as some models are more vulnerable to jamming due to limp wristing than others. Also, the  caliber of the firearm and the recoil force that can be withstood by the user all play a part.

Obviously, the major cause is because the frame was not held firmly enough during the backward movement of the firearm action. So, the easiest fix is to maintain a stronger grip, perhaps by using a two-handed stance with a pistol instead of one hand. Some of the good two handed stances we studied previously are: weaver stance, chapman stance, isoceles stance etc. Similarly, for rifles or shotguns, the user may try improving their stance or grip to make sure that the rifle is firmly braced against the shoulder before pulling the trigger.

In some situations though, the user may just be too weak to provide a good grip, or have some kind of physical deformity which causes issues. In this case, a modification will need to be made to either the firearm or the ammunition.

In the realm of firearm modifications, the user may simply pick another firearm of a different caliber or type. For instance, a firearm with a heavy steel frame absorbs the recoil energy better than one made of a polymer type frame and rely less on the user grip strength to operate.

Yet another firearm modification could be to reduce the stiffness of the recoil spring to make the firearm operate properly.

The user also could choose a firearm that uses a different mechanism to operate, which is not vulnerable to limp wristing problems. For example, the user could choose a single-action revolver to use instead of a pistol. Similarly, a rifle with a manually operated action may be picked instead of one that uses a semi-automatic action.

In the realm of ammunition modification, the user may simply use some different ammunition that burns with a different rate which could cause the limp wristing problems to go away.

In the video below, a person demonstrates using a loose grip with different pistols:

The interesting thing to note in the clip above is that not every pistol jams even with a loose grip and even the ones that jam do not necessarily do it every single time. Some, like the Glock 17, seem to be more sensitive to grip strength than others.

Happy viewing.