February 15, 2012

Failure to fire?

One of the guys in the office is a retired Law Enforcement Officer, and he sent me this yesterday. It was sent to him via a "retired cops email list" thing... I don't know if it is real, but perhaps someone can verify?

THE FOLLOWING TRAINING ADVISORY WAS FORWARDED FROM GWINETT COUNTY POLICE DEPARTMENT - LAWRENCEVILLE, GA

In September, a GCPD officer was involved in a situation which quickly became a use of deadly force incident. When the officer made the decision to use deadly force, the chambered round in his duty pistol did not fire. Fortunately, the officer used good tactics, remembered his training and cleared the malfunction, successfully ending the encounter.

The misfired round, which had a full firing pin strike, was collected and was later sent to the manufacturer for analysis. Their analysis showed the following: ".the cause of the misfire was determined to be from the primer mix being knocked out of the primer when the round was cycled through the firearm multiple times". We also sent an additional 2,000 rounds of the Winchester 9mm duty ammunition to the manufacturer. All 2,000 rounds were successfully fired.

In discussions with the officer, we discovered that since he has small children at home, he unloads his duty weapon daily. His routine is to eject the chambered round to store the weapon. Prior to returning to duty he chambers the top round in his primary magazine, then takes the previously ejected round and puts in back in the magazine. Those two rounds were repeatedly cycled and had been since duty ammunition was issued in February or March of 2011, resulting in as many as 100 chambering and extracting cycles. This caused an internal failure of the primer, not discernible by external inspection.

This advisory is to inform all sworn personnel that repeated cycling of duty rounds is to be avoided. As a reminder, when loading the weapon, load from the magazine and do not drop the round directly into the chamber. If an officer's only method of safe home storage is to unload the weapon, the Firearms Training Unit suggests that you unload an entire magazine and rotate those rounds. In addition, you should also rotate through all 3 duty magazines, so that all 52 duty rounds are cycled, not just a few rounds. A more practical method of home storage is probably to use a trigger lock or a locked storage box.

FURTHER GUIDANCE FROM ATF FIREARMS TECHNOLOGY BRANCH:

The primer compound separation is a risk of repeatedly chambering the same round. The more common issue is bullet setback, which increases the chamber pressures often resulting in more negative effects.

SOD RECOMMENDATION:

In addition to following the guidance provided above of constantly rotating duty ammunition that is removed during the unloading/reloading of the weapon, training ammunition utilized during firearm sustainment and weapon manipulation drills, should also be discarded if it has been inserted into the chamber more than twice. This practice lessens the likelihood of a failure to fire or more catastrophic results.


6 comments:

Old NFO said...

Yep, we know what happens when you do that in a SCAR... sigh

Jay G said...

OR they could go to the range more...

Just a thought.

Jeff B said...

Agreed, Jay, but...

(You just KNEW there was going to be a "but", didn't ya?)

Speaking only for myself, I have a different range ammo than I do a EDC ammo.

For range time, I pick up a couple boxes of cheap-tastic Federal 9mm Luger 115g JHPs. About $10/50 rounds at Wal-Mart.

EDC is Hornady TAP FPD 124g, at around $21/25 rounds.

So, I found this interesting because I do similar to the cop in the story: I have two magazines loaded, plus one in the chamber. Every Sunday, I cycle the mags, unloading the current ones and loading into two others (in an effort, however misguided or misplaced it may be) to not wear the springs faster than I must. And, until I saw this, I was doing pretty much the same thing: Unload and clear, empty the mag, reload into new mag, cycle a round, and repeat the next week.

Now I make an effort to ensure that the round that is chambered is always a round OTHER THAN the one that got chambered last time.

Julie said...

Must admit my first thought was the same as Jay G's ... if the guy ever fired the weapon this wouldn't have been an issue.

Sendarius said...

I can't get my head around this supposed failure mode.

How can the primer pellet have fallen from the primer?

The primer consists of three parts: the pellet of primer compound, the anvil , and the primer cup.

When the primer is inserted into the case, the anvil is pressed against the base of the primer pocket, and as a result its other side presses the primer pellet against the cup, where it can be ignited by the shock of the firing pin hitting the cup.

So the anvil (a piece of metal), is wedged between the pellet of primer compound and the base of the primer pocket in the cartridge case - how can the primer pellet fall out of the cup? Where can it go? It would have to somehow get past the anvil, unless the anvil itself were to somehow vanish.

I'm confused.

Sendarius said...

Just to clarify - the anvil is part of the primer only in Boxer-primed ammunition.

Berdan-primed ammunition has the anvil as part of the cartridge case.

Thinking of a Berdan primer makes it even harder for me to visualise the failure mode.