Repeat cycling of the same round can cause primer failure.

J

Joseywales3

New member
I knew that repeated cycling of hollow points can damage them, causing feed problems, but never considered this with primers:


http://smith-wessonforum.com/smith-w...37-danger.html


Quote:
THE FOLLOWING TRAINING ADVISORY WAS FORWARDED FROM GWINETT COUNTY
POLICE DEPARTMENT – LAWRENCEVILLE, GA

In September of this year 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:

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.

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.
 
Gotta say this is one that had never ever crossed my mind, and this is exactly how I treat my HD ammo. Since I shoot many more FMJ rounds than I could afford to buy if they were JHPs I'd just spit the JHPs out of the mag and load it up with range ammo every trip. I figured this kept me cycling my mags and that was good enough. I guess this means that I'll need to buy a big batch of HD ammo and just shoot a mag of HD ammo when I go to the range. Be a fair bit more expensive to shoot, but hey, it's worth knowing the first round will go bang, right?
 
I had heard of issues with bullet set back and concerns with other ammunition damage from repeated cycling, but never the specific issue with primers. I generally place my weapon in a lock box when not on me which eliminates the need to remove the chambered round. Also, I generally go to the range every week or so and always fire the entire magazine of carry ammo along with my practice ammo. I realize boxed ammo in a cabinet can last for a long time, but it does seem risky to carry ammo for a long period of time.
 
I never would have thought of that.
I imagine a lot of us - particularly those with kids - do the same.
Great post.

Honey, when I die, sell my guns for what they're worth and not what I told you I paid for them.
Click to expand...
lol
 
Just one more reason why I only unload my carry gun twice a year. Once it's loaded, it stays loaded. My older Son thought it was safer to unload and reload his carry gun each time he left the house until he dropped the loaded pistol while seating a magazine.
Two factors involved here.
1: EVERY time you handle a loaded gun is an opportunity to make a mistake regardless of your level of experience.
2: The smaller the gun, the higher the risk of a mistake during handling.

He now uses a childproof safe placed in a hidden area near the door so he can pick up and drop off his constantly loaded carry gun as he exits and returns.
 
I had never even considered primer failure, and I should have. An excellent lesson to be learned. My normal duty gun stays loaded pretty much all the time. When I do rechamber I ease the slide forward (not like a turtle, just easier than letting it go). I have posted this before and I have no intention of hashing it over again. I simply state what I do. I know the difference between fully in battery and anything else. For me at least, problem solved.
 
thank you.

I've been doing it. Load, unload again and again using the same JHP. Great post and very informative., Thank you very much.
 
Mods I think this is called for a sticky, this post was here a few weeks ago, it has helped a lot of people and more people each time it is posted. This is very important for those who carry.
 
I hope I am not too far out of line to say that I am very skeptical of this root cause analysis.

They have a sample size of exactly one round-how can they confirm that this particular primer ever had proper compound in it to begin with?

I would believe this analysis it if an experiment was done, repeatedly loading a sample of say 100 cartridges, and at the end a large percent did not fire.

Think of the recoil forces experienced by rounds in a magazine, impacting against the inside of the mag. If the "slight impacts repeated many times causes dead primers" theory was true, we would see the last round in a mag fail to fire more often than the first rounds. We don't.

Another reason to be skeptical is that in the age of the internet, where every rumor is repeated and amplified, this is the first time that I have heard of this. All of those people who must be re-chambering their rounds every day, and it has not become common knowledge that this practice can inert a primer?

If primers were really that easy to make inert, think of the protocols that the military would have to implement to keep ammo safe during transport. Have you ever heard someone say "that ammo is all duds, the road was too bumpy and the truck shook them too hard"?

Respectfully

Bob
 
Well, I won't argue that this wasn't just a CYA by Winchester. Still, repetitive cycling does damage the hollow points, so that alone makes it worthwhile to cycle through your SD ammo.
 
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