I hear from people regularly that they load and unload their guns often, sometimes on a daily basis. With revolvers this is not an issue, with things like semi-auto pistols and AR15s it is a dangerous practice.
Ref rechambering ammo into your pistol too many times;
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.
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.
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.
And another example;
Catastrophic Failure of Semiautomatic Handguns
The following bulletin was received from the New Jersey State Police – Officer Safety Division
Date: February 23, 2007
Continuous reloading an chambering of the same round may cause catastrophic failure in semiautomatic handguns.
The Security Force at the Los Alamos National Laboratory in Los Alamos, New Mexico, recently reported on the catastrophic failure of a semiautomatic handgun when it was fired. The internal explosion caused the frame to break while the slide and barrel separated from the weapon and traveled down range. No one was injured in the incident. An investigation revealed that security personnel were repeatedly charging the same round of ammunition into the chamber.
Technical personnel at Glock Inc. advise that repeated chambering of the same round may cause the bullet to move deeper in the casing, further compacting the propellent. When a normal cartridge is fired, the firing pin his the primer, igniting the propellant. When the propellant burns, the gas pressure drives the bullet out of the case and down the barrel. However, if the propellant has been compact, the pressure may increase beyond the gun’s specifications, causing the weapon to break apart. Sigarms Inc’s personnel confirm that reloading the same round five or six times will cause the problems, noting that reloading the same round even once will void their warranty. Both manufacturers stress that the problem is not with the gun, but with chambering the same round repeatedly.
The NJ Regional Operations Intelligence Center urges all law enforcement officers not to chamber the same round when loading their weapons.
***For example, when you clean your weapon, most of us drop the magazine and then pull the slide back thereby ejecting the round in the barrel. After cleaning the weapon many of us will return the “same” round to the barrel that we initially extracted. Each time the slide slams forward on that same round it seats it deeper into the cartridge. Apparently, by seating the round deeper into the cartridge, it creates greater pressure when the round is intentionally detonated by a firing pin strike and is causing weapons to explode.
If one is worried about child or family safety, the use of a pistol safe is a vastly better alternative to loading and unloading your carry pistol daily.
If you simply must unload/reload daily for whatever reason, lets say you have one pistol and you keep a daily dry fire/training regimen, I strongly urge you to not re-chamber the same round more than 2-3 times, and to keep track of this to mark the round coming out of the chamber with a Sharpie so that you know how many times it’s been chambered. A tic mark on the rim of the case is easy to do, and easy to see. Rotating the ammunition through the magazine so that all of the rounds are used equally is a good idea. Better yet, if one can afford it, is to buy sufficient carry ammunition so that a chambered round can be thrown into the training ammo can and used at the range, and replaced with a fresh cartridge.