What kind of jam is this?
 

What do you call the kind of jam where the front of a round goes into the chamber but the bolt doesn't go forwards all the way? Is it just a failure to feed or is there a more specific name for it? I ask because I have noticed it happening a lot in the most recent series of Strike Back with their P226s and wanted to call it the correct thing. Here is an example of the kind of jam I am talking about:

http://www.imfdb.org/images/thumb/0/...S04E05_250.jpg

Also, it seems like this kind of jam disproportionately happen with guns in TV/movies, is it a side effect of being blank modified? My guesses are that it was either the blanks were more fragile without a bullet so could be warped out of shape meaning they don't feed correctly, the powder in blanks doesn't burn as cleanly or completely meaning there is a lot more fouling in the chamber, or the main spring is weaker in order to allow it to cycle blanks but doesn't always have enough force to chamber a round properly. Is any of this the case?

In the Army, we would call that a "failure to return to battery"

My guess would be fouling combined with the modified spring.

Yeah, it's out of battery.

Thanks. I was hoping that it had a nice snappy name like "partial feed", or something like that. I vaguely remember being taught that it was called a "failure to close" but can't really remember. "Failure to return to battery" is a bit long winded (as well as seeming pretty vague to me, as that could mean that the slide is anywhere between fully back and full forward, by any cause).

Also, is this type of jam relatively rare in live firing guns, as I don't recall it ever actually happening to me without deliberately doing it by riding the bolt/slide forward. However I keep my guns pretty clean and am an obsessive "forward assister" due to being taught on the SA80 platform where it is part of the loading and stoppage drills.

Just a general question, does the forward assist just ram the round into the chamber and force the bolt closed? If so, wouldn't it be a bigger problem if the shell casing got stuck in the chamber? (I never had a gun with a forward assist.)

Yes. If you examine the bolt carrier of an M4/M16 type rifle, there are these little notches in it. The forward assist interfaces with those notches to, yes, ram the bolt and carrier forward into battery. This is only useful for this failure to return to battery type jam, and only as long as the gun isn't too fouled by carbon buildup or external debris.

Certain guns have no need for this as they have inherent forward assists, like the AK's charging handle being directly on the bolt, or the slide on a handgun, the piece that interacts with fed rounds. Additionally, you'll hear people refer to the slide as the "bolt" because they probably also handle M4/AR type rifles and it's just the vernacular, but there isn't really a "bolt" with handguns (except maybe the Desert Eagle), just a slide, which more or less serves the same functional purpose. The More You Know.

Doing a forward assist could potentially jam a malformed round into a chamber, or a normal round if the chamber was really dirty. However, the force of the gas system on the bolt is stronger than that of the bolt spring (otherwise the gun would never cycle) meaning that if there is too much friction in the chamber to prevent the spring from locking the bolt hence requiring a forwards assist, the gas pressure would normally be more than enough to overcome this friction to extract the round. Also, I think that there would probably still be a slightly higher pressure in the chamber giving the case a slight blowback effect.

Which is always wise to actually see what kind of jam you have on your gun before you do anything to it like smacking it needlessly

When you can it is definitely a good idea to work out why a stoppage happened, but if you are in a firefight you will just follow your immediate action drills. Tap the magazine, open the bolt, look in the chamber, if clear release the bolt, forward assist, shoot. You will probably have no idea what type of jam it was other than it is now fixed. Depending on how much of a rush you are in you might not even look in the chamber as that is only useful if you have a double feed, which is relatively rare in comparison to other stoppages.

No that is the old way of doing it. Marines don't even use the forward assist during a jam today. It's either tap, rack, bang if you are in a pinch or look at the chamber to see if its a double feed or stovepipe, solve it and get back into the fight as fast as you can. With SPORTS, you don't know what is wrong with your rifle but you are already trying to solve an unknown problem. And SPORTS isn't immediate action. It's remedial action.

Yeah, it is always tap, rack, bang. ALWAYS.

I've never used the foward assist, and frankly, think it is both stupid and dangerous.

But I have certainly tapped, racked, and went bang a few times. It just works.

Whether or not to do immediate or remedial action seems to be preferential though. It's the difference between spending 3 seconds to perform an action to solve one or two problems, or a few more seconds to perform an action that will solve nearly all problems one could conceivably have. More importantly though, at the end of the day, one has to worry about fixing their gun, and if they choose to go one way or the other, the only thing that makes that a bad decision are the semantics of the situation, and the jam itself (which is unknown).

Having had a majority of jams with the guns I've fired that either required remedial action, or a simple lovetap on the back of the slide, I've come to A: not rely on tap rack bang, and B, check my gun to see what the problem is before acting. I assess what the problem is and tackle it. I don't robotically train myself to do one or two things every time my gun stops assuming it may fix the issue, I train myself to analyze the problem and act accordingly so I KNOW the problem will be fixed. I personally think, even if a split second slower, it's better to act on knowledge than acting on a hope and a training scar.

To stay relevant, if the guy in commando's picture were to go tap rack bang, he may fix the problem, sure. He may force a double feed and have to go remedial too. If he takes half a second to check that he's got a round half chambered, he can tap the slide and be back in business, granted the round is live.

I'm surprised you don't consider this logic, Excalibur, as it's right out of the Magpul DVDs and it makes more sense than robotics.

I thought SPORTS was the immediate action, whist remedial action involves putting the safety on and removing the magazine doesn't it? I was taught the British way which is a bit different, the "immediate action" is just to safe, cock, hook (lock the bolt back) and look. From their you perform the relevant "stoppage drill" depending on the situation.

The drills may have modernised since I was taught though (also I was Navy not Marines or Infantry so our small arms training may have been different and not as comprehensive). We tended to shuffle them around a bit (tap magazine first) and ommit parts depending on the situation. Due to the fact you have to reach over the SA80 to cock it you pretty much look in the chamber anyway whatever you do, so there isn't really a simple "tap, rack, bang" unless you deliberately avert your eyes.

In the British forces it is standard to do a forward assist, even on a normal load. It is arguably unneccesary as it was only really needed with the A1 guns and the bolt closing problems mere largely solved with the A2, but I don't think I would ever call it dangerous. In order for the FA to do something dangerous on an M16 I think you would abolutely have to batter the thing, to the point where you would probably break the plunger.

I do think having the forward assist is a necessity on the AR-15 platform though, as if you were stuck in a fight with a dirty chamber that caused the bolt to not reliably close you would be buggered without it.

I wasn't advertising to train until it's robot motions. The part where you observe to see why your gun stopped working is the important part.