Your AR-15 is a gas-impingement rifle that is a bit more complex than a rifle with a bolt action, and certainly more so than a single-shot platform.
There are a whole host of things that could in theory go wrong with an AR-15’s action, and which do in practice, some of them not infrequently.
Regardless of whether you have a rear-charger, a side-charging AR-15 rifle, or have built one with a lefty ejection port, the following four problems are among the more common you may yet encounter.
Here are some high level notes for diagnosis and redress.
Failure to Feed
Failure to feed is most likely the simplest of AR-15 malfunctions, and it occurs when for some reason or another the rifle does not strip a round from the magazine or the action does not fully engage battery.
Failure to feed can be caused by a weakened buffer spring that does not return the bolt to battery. On a rear charger the redress here is simply to tap the forward assist. On a side-charging AR-15 upper, you just tap the charging handle until the action locks closed.
Failure to feed can also be a problem of the magazine. First, give the magazine a tap to ensure that it is seated properly in the magazine well. If that does not resolve the problem, it could be a weak mag spring. Remove and replace the magazine and see if that fixes the issue.
Two other problems, though not the most common, are known as “double feed” and “brass over bolt,” respectively.
In a “double feed” there are two rounds that get jammed into the action; usually this is one empty casing that has not been properly cleared, and a fresh round from the mag. Rack open your action so that the charging handle stays out of the way, then drop the mag and manually clear the action before proceeding.
In the case of a “brass over bolt” what happens is that a casing, or in some cases, a live round, gets wedged between the top of the bolt and the roof of the upper receiver inside the action. To clear this, you will need to drop your magazine, then rack back the charging handle. It might require you to tap the butt on the ground (of course, keeping your rifle pointed in a safe direction) in order to get the round unstuck before you can proceed.
While this is not an exhaustive compendium of potential failures to feed, these are among the more common ones that you may experience.
Failure to Fire
Failures to fire are not particularly common, and they occur when a round is properly chambered, the operator pulls the trigger, but the gun does not fire.
The first thing here is safety. If you have a failure to fire, keep the gun pointed in a safe direction, with the action closed, for at least a minute before you attempt to clear it.
There are two main causes of a failure to fire. One is that the ammunition was defective, in which case the round should be discarded and a fresh round chambered, and the other which occurs when the firing pin does not strike the primer with enough force to fire it.
If you experience repeated failures to fire, that is almost certainly the case, and the solution would be to replace your firing pin spring.
Failure to Extract
A failure to extract occurs when a spent casing, or part of a spent casing, remains in the chamber. This can be a very serious malfunction because it is not identified and the operator attempts to load and fire another cartridge, it can cause a catastrophic failure of the chamber or barrel which can cause serious injury.
If you suspect a failure to extract, immediately lock the bolt open, place the safety selector on safe, and remove the magazine. Inspect the chamber from the rear to assess the situation. If the casing is intact, you may be able to remove it with a pick the point of a knife, by prying at the rim.
If it has ruptured and only part of the casing is inside, you may be able to dislodge it by tapping the butt of the rifle on the ground.
Either way, failures to extract can be caused by a dirty or corroded chamber; this is something you will want to investigate as soon as you return from the range. The other thing could be a weak extractor spring, in which case that part must be replaced.
Failure to Eject
Lastly, we have a failure to eject, which manifests when, for some reason or other, the spent casing is extracted but not ejected clear of the action, hence the name.
The most common “type” of failure to eject is known as a stovepipe jam, which is so named because the spent casing will stick out of the ejection port at an angle, between the ejection port and the bolt carrier group, like a stovepipe.
This is easy enough to clear. Open the bolt and manually clear the spent casing, then resume firing. If the jam doesn’t occur again, you had a one-off stovepipe.
If the problem repeats, then you need to look into the cause. There are several potential causes of stovepipe jams, but one of the most common is a broken ejector or a fatigued ejector spring. In that case replacing the affected parts should solve the issue.
Build a Better AR with the Help of Gibbz Arms
No AR-style rifle is immune to the malfunctions explained in this article, but there are still avenues available to you by which you can build a rifle that is easier to inspect or clear, or which is better suited to your own natural abilities.
Whether that means building a rifle with a lefty ejection port that’s more ergonomic for you as a left-handed shooter, or building a side-charging AR-15 rifle that’s easier and more intuitive to manually clear and inspect, we have you covered.
Shop our collection of side-charging AR-uppers, uppers with lefty ejection ports, and pistol-caliber uppers to find what works for you, and get in touch with us if you have any questions about part specifications, performance or compatibility.