The Failure to Eject
In a failure to eject type of malfunction, the fired cartridge case is extracted from the chamber. However, it does not get ejected with enough force to clear the ejection port. The base remains partially in the gun, getting captured between the bolt face and the chamber mouth.
One of the reasons for this happening is a light load that does not allow the slide to travel its complete length, coupled with the lack of ejection force strength. Those factors contribute to the shell case not being able to clear the ejection port. The slide then moves forward with the shell case pressed against the bolt face. Because of this, the slide cannot close, and the gun gets jammed.
The Stovepipe Jam
Note that in the accompanying image of a typical stovepipe jam, an empty cartridge case is stuck in the ejection port, sticking out the top of the pistol. This is an example of a classic 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 sticking out above a roof line.
A stovepipe jam usually occurs in semi-automatic or fully-automatic firearms. It is a failure-to-eject type of malfunction where the cartridge that was just fired did not get ejected from the firearm properly and is partially stuck in the ejection port. This means the weapon cannot load the next cartridge into the chamber properly and will not fire.
What causes a stovepipe?
There are four main causes contributing to stovepipe jams. The first type being what is referred to as limp wristing the weapon, or not holding the firearm firmly enough to offer the required amount of resistance and rigidity against the recoil forces of the firearm. Because of that lack of resistance to the firing action, the recoil forces may not complete their cycle properly and a jam occurs. This is more commonly seen when using handguns as opposed to long guns, which are supported against a more rigid shoulder.
Old, lightly loaded, or bad ammunition can also be a culprit. The propellant in the cartridge case may have degraded due to age, or the case may not have been filled with enough propellant which can both be causes. Either way, the burning propellant doesn’t generate enough power to cycle the action properly, so the cartridge doesn’t get fully ejected by the time the slide starts its return back into battery.
A bad or damaged ejection mechanism can also create the problem. Either the return spring of the slide may be too strong, or the extractor or extractor spring that extracts the old cartridge is too weak and does not allow the ejector to do its job. In either case, the slide moves back, until it gets pushed forward. The slide starts to close before the old case is fully ejected. Therefore, the old case gets caught before it has a chance to fully leave the firearm.
The ricochet is when the fired case does get ejected, but it hits something on the way out (e.g. 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 from that when configured with a snail-drum magazine that fed from the left hand side. It did not exhibit this issue when configured with a box magazine fed from the right hand side.
Clearing a Stovepipe
As can be seen clearly in the picture above, the empty cartridge case was not fully ejected out of the firearm. The case became caught between the slide and the hood of the chamber, preventing it from closing fully. Therefore, the pistol jammed. Fortunately, stovepipe jams are relatively easy to clear, without using any tools.
To clear a stovepipe, simply use your weak-side hand to sweep over the top of the slide — front to rear with authority. That action will displace the case. The force of the mainspring will force the gun into battery with a fresh cartridge ready to be fired. As stated, the primary cause of this problem, in handguns, is cause by limp-wristing. However, if the problem continues to happen, the extractor, ejection spring, or return spring (or more than one of the above) may need to be replaced.
The Slamfire Malfunction
Another type of malfunction is the slamfire. When a new cartridge is being loaded into the chamber of the firearm, sometimes the bolt slams the cartridge into the chamber with such force that the weapon fires without the user having pulled the trigger. This is known as a “slamfire.”
A slamfire is particularly dangerous because it happens when the user is usually not expecting. In some firearms, it can happen when the user’s finger is off the trigger. In the case of semi-automatic weapons, it may cause them to keep firing until the magazine is empty. Since a slamfire comes as a surprise to the user, it can cause the user to lose control of the firearm and point it in an unsafe direction.
Slamfires are a more common occurrence in weapons that have a free-floating firing pin, than in weapons that have a spring-loaded firing pin. When a semi-automatic or an automatic firearm is fired, the hammer strikes the firing pin, which then moves forward to strike the primer. This sets off the chain of events that forces the bullet to exit the barrel.
Some of the resulting recoil force is harnessed to cycle the reload procedure of the firearm automatically. The recoil force pushes the bolt backward. As it moves back, an extractor claw pulls out the cartridge that was just fired. The bolt continues to move backward and compresses the main spring. Meanwhile, the extractor claw pulls the empty cartridge case backward, until it can be pushed out via the ejection port.
Meanwhile, the bolt moves to its backward most point until its momentum is overcome by the compression of the main spring. The cartridge case is then pushed forward again by the force of that return spring. On its way forward, the bolt face picks up a new cartridge from the magazine and pushes it into the chamber.
As the bolt reaches the chamber, the firing pin continues to move forward due to inertia, until it is stopped by the cartridge’s primer. Now, if the firing pin is spring loaded, the spring slows down the firing pin, so it does not slam against the cartridge’s primer hard enough to ignite it. However, if the firing pin is free-floating, there is nothing to slow it down as it slams into the cartridge’s primer.
In either case (but especially for free-floating pins), there is a chance that the firing pin slams into the cartridge primer a little harder than expected and could cause it to detonate prematurely. This causes the firearm to discharge without the user pulling the trigger causing the slamfire where the cycle can repeat.
Free-floating firing pins are more common with military firearms, so there is a greater chance of slamfires occurring with them. Of course, this is not to say that firearms with spring-loaded firing pins are immune to slamfires, because it can happen with them as well. However, it is not as likely as guns with free-floating pins.
Slamfires can also happen on some bolt-action firearms when the user is manually cycling the bolt and pushes it forward a little too hard. Some of the causes for slamfires may also be dirt or corrosion. If enough dirt gets in the bolt’s firing pin channel, it could cause the firing pin to stick to the bolt wall and protrude out of the bolt. This could cause a slamfire.
The same thing could happen if corrosion causes the firing pin to protrude out of the bolt. Ammunition could also be at fault. Some ammunition is manufactured with more sensitive primers than others and require less force to detonate, and that could cause slamfires.
Preventing a Slamfire
The solutions to fix those causes are as simple as keeping your firearm clean to prevent dirt from jamming the firing pin and ensuring to use cartridges with less sensitive primers, so more force is needed to detonate them. This is why military cartridges usually have harder primers, so they need an actual hammer strike on the firing pin, rather than inertia, to detonate.
Another solution is to use firearms that are designed to minimize slamfires. For instance, the firing pin should have a spring around it, so that it slows down the firing pin as the bolt slams forward. The spring provides enough resistance that the pin will not hit the primer hard enough due to inertia, but will detonate the cartridge when the back of the firing pin is struck by the hammer. Another field fix is to make the firing pin as light as possible. In that way it doesn’t transfer enough force to detonate the primer due to inertia.
Some models of firearms are more susceptible to this problem than others. If this is a concern, do some research into the design of a firearm before you purchase it.
This is not a subject I thought I should be familiar with. However after reading the many responses with similar experience, I will spend more time learning about issues that I could find myself dealing with. Thanks Ed.
@David. If you would like it to flawlessly run all that other ammo that it wouldn’t this time, may I suggest: Replace the firing pin, the extractor, and the extractor spring, with much better quality from say an aftermarket place like TandemKross, who has a package for the M&P 15-22 for about $50. There are probably other aftermarket companies out there too, but I do know from experience, [TK] is a very good company, with very good customer service. Once you get all the parts, clean your bolt up, and lube EVERYTHING in/on the bolt with Wilson Combat Lube, as it puts a very fine film of SLICK on with only a drop or two, does not run, and to remove it has to be cleaned off with something like Hopes #9, so it stays slick. Doing this you will probably notice a smoothness to your bolt function that has never been there before, and should function flawlessly with any .22LR ammo with the possible exception of the super LOW velocity, like the 750 FPS, stuff. If you still need other, yet stronger springs, it is hard to beat Power Custom Springs. When you can get one to run pretty much any ammo, including the cheap bulk ammo, the $50 expense is worth every penny. The big downside though is; you will run out of ammo faster, and thus need more. 🙂
My First and Only “Slam Fire” events occurred with my Hungarian SA-85M.
Needless to say it can be quite unnerving! Especially when it results in a “Burst Fire” of 3 Rounds in Automatic Succession!!
This occurred with a quality made American, Boxer Primed Military Ammunition.
Much to my dismay I discovered that it did indeed have a “Free Floating” Firing Pin in tha Bolt and I took her off Active Rotation until I was able to obtain a “Spring Loaded” Bolt Assembly to replace the original.
Subsequent Range Testing proved the malfunction to be corrected (except for Primers with the Thinnest Cup Material).
I was lucky enough to be strictly following the rules of Safe Firearm Handling when my Malfunctions occurred and the Muzzle was pointed In a Safe Direction but a Jarring Lesson like this can Drill that Lesson Home so that I “Never” Fail to keep the Muzzle pointed in a Safe Direction, Even when I have No Intention of touching the Trigger.
I experienced slam fires with my S&W M&P 15-22 firing CCI Velocitor ammo. Those rifles are notorious for poor failure to eject with “weak” .22LR ammo, so I figured a hotter round would be okay. A little too okay, it seems! Ended up buying a couple boxes from several different manufacturers (Winchester, CCI MiniMag, Aguila, Norma). At the end of the day, only the Norma TAC-22 40gr LRN went through all 100 rounds without a single failure.
I remember when the dept. I worked for switched over to the then new M&P .40… us as instructors never had the problem when qualiyfing ourselves to be instructors for our veteran officers and incoming recruits… but when we had the veteran officers on the line slam fires happened a pretty fair amount. Mainly because we had a LOT veteran officers we had to get qualified so these new pistols were getting some pretty heavy usage. It was combo of the channel the striker assembly rides in getting too dirty… of course keeping the firing pin out along with an issue that would happen if you slammed the mag home on a reload the slide would drop on its own. Thankfully on our rapid reload section the reload mag only had one round in it. Still, not fun. To correct the issue we had to increase the cleaning intervals above what Smith recomended. Their manuals were apparently changed to reflect that. Something else discovered was that these were new, basically fisrt off the assembly line to fufill a large contract… that the striker’s retainer/return spring was a little too weak and would let the firing pin come forward when the slide closed and of course… BOOM… the real fun was when someone would slam a mag home and the slide would drop on its own on a mag that more than one round in it. THAT issue was QUICKLY resolved by Smith by sending us armorers stiffer springs. I still don’t know if Smith has ever corrected the slide dropping on its own. And honestly the only thing I think would fix that would be to put a stiff slide lock spring in. We suggested it to Smith but unsure if they ever implemented it. I think even my Shield Plus will do it if pound the mag home hard enough. I know my older M&Ps and SDs will drop it if smack the mag in with decent enough force. Be safe with whatever you’re using.
In 1911-style pistols, the firing pin should not protrude from the slide face when at rest with the hammer down. To test this, clear the weapon, lock back the slide, and press in the back of the firing pin until it’s flush with the backplate. You should be able to see the front end of the pin recessed in its hole, but it should not have positive protrustion, ie. stick out. Positive protrusion significantly increases the risk of slamfires, and should be corrected by a qualified gunsmith.
In a lot of older “pocket pistol” semi-autos, the firing pin does double duty as the ejector, so correct firing pin length to prevent slamfires is even more important.
Sweeping a stovepipe with your bare hand can cut or burn your hand. An injury during a fight is not an advantage. Instead: tap the magazine with support hand, rack and flip to clear the casing, back on target, back on trigger and make the conscious decision to shoot it not.
Slam fire is a broken gun, defective ammo, or both and is deadly. Find and fix the problem and do not fire the gun until resolved. Period.
Let’s be smart about this.
I am beginning to believe the Extractor is miss named. I believe it would be more accurately named something like; “shell holder”. Yes, if pulling a loaded round from the chamber, it would actually be extracting, however when a round is fired, it is that force that pushes the empty case against the bolt face, forcing the slide rearward with great force, so in this process the extractor is not actually extracting, however if it is incapable of “Holding” onto the casing as it pushes rearward, while being racked across (hitting) the next round in the magazine which is trying to pull the fired case from the “shell holder”, then you get a stovepipe, or at least a Failure To Eject. Thinking this way is why, in many cases, installing a heavier extractor spring fixes the problem, especially in examples of the Ruger 10/22, and the Ruger MK series (think Power Custom Springs). The Ruger PC Carbine, has some reviews of frequent stove piping. In this case the OEM extractor hook profile is almost non-existent. The hook on the Ruger PC extractor is more like a burr than a hook, it does not hold well, but fortunately there are a couple aftermarket companies who offer not only a hardened tool steel extractor, but also with an enhanced hook profile which really locks the casing on the bolt face when until the casing can be ejected by the ejector, and thus eliminating the Failure To Eject all together. On the other hand, I have found that Failure To Feed issues are mostly due to magazine issues, like the follower nose-diving (the bolt moving forward grabbing the top of the case rim, due to physics, the shell tip tries to rotate downward at the bullet end, and the casing actually catching on the front of the magazine stopping forward motion) while loading the next round, dirty or too dry, and weak springs. Sometimes the fix is as simple as bending the top round of the magazine spring under the magazine follower, UP, counter acting the nose-diving, allowing the casing to pass the front of the magazine. The Failure To Feed issue is so prominent in the Glock 44 that Glock actually has a video on their webpage, of how to eliminate this issue by loading the magazine correctly. While this video is directed at the Glock 44, I have found it also works on other manufacture firearms as well, and thus a good method to use on all magazines. If you have either issue, Failure To Feed, or Failure To Eject, DO NOT LIVE WITH IT, instead research, try things you learn, like the Glock video, but it seems like many just want to blame the ammo. If you go the “it’s the ammo’s fault route”, you may never resolve the root cause for the failures. Any modern well maintained firearm should be able to run trouble free for hundreds, if not thousands, of rounds, so do not live with failure issues, learn from them.
Winchester Model 100’s are notorious for the slam fire deal, and there is/was a recall for them to get hardened firing pins (if I remember correctly) The pins would slightly deform and end up sticking out just a bit. Had it happen to me on a gun my dad gave me (308). Thing cooked off the remaining 4 shots on what seemed like a full auto mode. Quite startling and not sure the barrel enjoyed it either, as it was steaming for quite awhile (deer hunting in Minnesota and yes, I got the deer – not which shot tho 🙂 )
One malfunction missed by the author is a bad magazine. The front lip of the magazine bottom on the old military 1911 mags were known to bend down after heavy use – allowing the magazine to go too far into the mag well – catching the slide during the firing sequence. The field fix was to bend the lip back up. The final fix is to buy good after market mags.
A major issue causing Failure To Load is the weakening of the magazine spring if the magazine is left fully loaded for a period. In this case Fail To Load occurs on the last one or two rounds in the magazine. The mag spring simply does not have enough force to put the last round in the firing chamber. Stretching the spring helps, but it never regains its OEM force. You see this by fully loading the magazine after stretching the spring to its original length (found by buying a new OEM spring), then emptying the magazine and measuring the new spring length. It will be shorter than when you stretched it. How much shorter tells you the future usability of the spring. Other methods of measurement are using digital trigger gauge to see the force required to depress the follower to the top of the empty magazine, or measuring the length of spring sticking out of the bottom of the empty magazine when the floor plate is removed. Scrubbing the ramp in the barrel that the cartridge follows into the firing chamber doesn’t seem to make much difference. All this testing was done with Glock 17 OEM, ETS and Magpul mags. I have not tried measuring the Korean G17 mags.
I bought a Tisas Zingana PX9 and have a constant problem with stove piping. This information is a game changer! Of course I blamed the firearm because it surely couldn’t be the operator. LMAO! I am an older shooter with a bad case of arthritis in both hands, so thinking on the poor grip statement makes all kinds of sense! A lack of strength training is also a problem. Thank you for this information! Now I can get to doing some other types of training and quit blaming the firearm.
I have Never personally had a slam-fire, But on the flip side I have had a few stove-pipes, They tended to occur on days when “Old-Guy” didn’t really feel like shooting and was limp wristing the pistol,…. Or I had not emptied the mag in a while and the spring “went flat” ( honestly, I’m told my PK-95PR went out of production for that reason ). What I do is clean the pistol after a few months anyway and disassemble the mags measure the spring if its short, I clamp it down and Pull it back to length, refill the mags and put it back in the paddle holster, the reason for the clamping is that the springs tend to twist during stretching out, This thing is my truck gun and good for that use,…. For EDC, I stick with Old Faithful, The Black-hawk, and the magnum cylinder, and for the range I use all my old 9mm in the short cylinder, and just burn it up And Since the Auto ticker is stainless, I shoot 147gr Tula, the Black-Hawk dislikes removing cases if I shoot the lacquered, So factory new is the order of the day there.