Man on Fire

[chowder]

In this film Denzil Washington puts a gun to his head, pulls the trigger but the round doesn't fire even though there is a dimple mark on the primer showing that the firing pin had made contact.

Is this sort of misfire possible?

[Johnny L.A.]

Yes. The firing pin hit the primer, but the primer was a dud. Without the primer, the charge is not ignited.

(I haven't seen the film, so I'm answering the question generally.)

ETA: Primers

A cartridge primer is a small copper or brass cup, containing a precise amount of stable but shock-sensitive explosive mixture, with ingredients such as lead azide or potassium perchlorate. Cartridge primers are 4 to 6 mm in diameter (standard sizes are 0.175 inches and 0.210 inches for handgun and rifle cartridges).

A striker hits the outside of the cup, which deforms, and the explosive is crushed on an anvil. The shock-sensitive chemical compound explodes, igniting a secondary charge of gunpowder or other explosive.

[chowder]

[quote=Johnny L.A.;10361223]Yes. The firing pin hit the primer, but the primer was a dud. Without the primer, the charge is not ignited.

(I haven't seen the film, so I'm answering the question generally.)

Yes but later in the film Washington gives the bullet to another guy and this time it works.

So obviously the primer wasn't a dud

[Euthanasiast]

There is indeed the possibility that the firing pin simply didn't get a good enough strike on the primer (bent or clogged in some way) or that the primer has malfunctioned in some way, and given another try, would fire normally. It is also possible that the primer would have a mark or small dent on it without going off.

There is the primer, and then there is the powder charge that allows for the full explosion that forces the bullet from the hull and down the barrel of a gun. I have heard of bullets with only a primer and no powder charge still generating enough explosion to kill someone (at very close range).

Bad rounds were more common back in the old days, and this is one of the reasons that revolvers were better guns, because if you got a bad round, you simply pulled the trigger again and the next bullet would be moved to the firing position. With an automatic, you'd need to clear the round by cycling the firearm.

with all of the technology in use today in the manufacturing of bullets, finding a bad round is about as difficult as winning the lottery. Oh, and if your life is on the line, it sucks worse.

[BrotherCadfael]

Misfires are quite common in literature, but I have never seen one in real life, out of thousands of rounds fired. For the number of strikingly well-timed misfires to occur in anywhere near the numbers you see in books and films, two-thirds of factory-made rounds would have to be bad.

[Just Some Guy]

Originally Posted by BrotherCadfael

Misfires are quite common in literature, but I have never seen one in real life, out of thousands of rounds fired. For the number of strikingly well-timed misfires to occur in anywhere near the numbers you see in books and films, two-thirds of factory-made rounds would have to be bad.

Come on, they waste a lot more bullets than that firing wildly at the hero and missing.

[muldoonthief]

FWIW, I once bought several hundred rounds of surplus .223 ammo (I seem to remember it was Korean) for a new bolt action rifle. It misfired about 25% of the time - good firing pin dimple on the primer, but no boom. I sold it to a guy who owned an AR-15 - his rifle reliably fired all the ammo, and was able to fire some, but not all, of the rounds which had misfired in my rifle. And when I bought commercial .223, my rifle fired it all with no problems.

[FallenAngel]

This kind of thing is more common in weapons that have a "trigger job" to lighten the amount of pull needed to pull the trigger all the way back.

Simply put, pulling the trigger releases the spring energy and causes the hammer or striker to push the firing pin into the primer.

Most handguns are manufactured with a "stiff" triggers. This is also known as "lawyer-proofing," in the belief that making the trigger harder to pull adds to the relative safety of the weapon.

It also makes the weapon more difficult to fire accurately, since the hand shakes as a result of the tension needed to pull it fully, particularly in double action mode where the hammer is not cocked beforethe trigger is pulled.

When I had a trigger job done on one of my handguns, I asked the gunsmith to put the double action at eight pounds of pressure. He recommended I not go less than 10, in case I ever got ammo with "hard primers," or primers that take a relatively high amount of impact force to set them off. If you had a too light spring and a hard primer, the pin would dimple the primer but not set it off.

[Don't fight the hypothetical]

Echoing other posters, yes it can happen. I've had it happen to me (well, without the gun to the temple part).

ETA: One of my favorite movies

[outlierrn]

Originally Posted by muldoonthief

FWIW, I once bought several hundred rounds of surplus .223 ammo (I seem to remember it was Korean) for a new bolt action rifle. It misfired about 25% of the time - good firing pin dimple on the primer, but no boom. I sold it to a guy who owned an AR-15 - his rifle reliably fired all the ammo, and was able to fire some, but not all, of the rounds which had misfired in my rifle. And when I bought commercial .223, my rifle fired it all with no problems.

Not apropo of the OP, but, IIRC, there are some differences between civilian .223 and military 5.56 mm weapons and ammo resulting in compatbility issues

[Happy Scrappy Hero Pup]

Originally Posted by Johnny L.A.

The firing pin hit the primer, but the primer was a dud.

So he reached in the Miller cooler, grabbed a cool Bud?

[chowder]

I forgot to mention that the gun used in the film was an automatic.

Whether this makes a difference or not I've no idea

[UncleBill]

Or, "semi-automatic", as the case may be.

[muldoonthief]

Originally Posted by outlierrn

Not apropo of the OP, but, IIRC, there are some differences between civilian .223 and military 5.56 mm weapons and ammo resulting in compatbility issues

Yeah, I've only used .223 in that rifle since. I'm betting rock hard primers though - while the bolt action put a definite dimple on the primer, the AR put a much deeper one. Makes sense for military ammo - which gets subject to a bit more abuse in the field than commercial.