question about re-chambering a round

Discussion in 'Ammo & Reloading' started by GunnerGSP, May 17, 2012.

  1. GunnerGSP

    GunnerGSP Active Member

    OK. So I stumbled on this website the other day and was looking around. Kinda interesting until I saw this and then I was like "huh"? :confused:

    http://www.glockfaq.com/

    The read from the website is below in quotes. I have never heard this. So have I missed something along the way? But first my question.

    Depending on where I am and what I am doing, I will shift between firearm condition levels. I am not looking for an "is this the best way to carry" discussion. I carry condition 1 when out and about. Anyway, when I clear my gun for the range or cleaning, I have to eject the round in the chamber. What then are they suggesting below? I don't shoot my carry ammo too much due to the cost. I do shoot it, just not that much. So what carry ammo I have, I plan to keep for a while. Thoughts on this?

    ********
    "Why is it so dangerous to re-chamber the same round more than once?
    Loading/Unloading Magazines -- Caution!

    Constantly loading and unloading mags can cause deadly consequences for the unsuspecting pistolero! Reduced OAL is one of the primary causes of second shot stoppages (SSS) -- when the pistol fires the first round in the chamber, but malfunctions on the second round. This has been a serious problem, especially with some LEAs, and has resulted in much consternation about certain pistol brands or brand models.

    SSS problems are more of an ammo/operator issue and have little to do with the gun. The most common reason for SSS is reduced ammo OAL caused by loading and reloading the same two rounds over and over. The sequence goes something like this: remove the mag, cycle the chambered round out to unload; put the mag back in to reload; cycle in the next round; then put round no. 1 back in the mag.

    Typically, these two rounds could go through several load/unload sequences. The OAL of those two rounds may be reduced even after the first load/unload sequence. Seating depth is commonly .020" to .030" deeper than it should be in rounds that have suffered this abuse. When the OAL is reduced this much, the feed angle changes enough to present liability problems. Such rounds can also produce dangerously high pressure levels. This problem is one of the suspects in .40 S&W kaBooms!

    So to prevent this, keep a close watch over your loading/reloading procedures and make sure that a round is not bumped against the feed ramp -- no more than once. Move rounds that have been hand-cycled out of the load/unload sequence. Closely inspect your carry ammo to make sure that OAL hasn't suffered. It is recommended that you not carry the same ammo for more than three months under any circumstances. [JT]"
     
  2. bhale187

    bhale187 New Member Supporter

    Here's something I saw awhile back, scary to think about

    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 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.
     

  3. GunnerGSP

    GunnerGSP Active Member

    So is this common knowledge/practice?

    How did I miss this?

    Edit: I have kids in the house, so depending on the situation, I will unload my weapon.
     
    Last edited: May 17, 2012
  4. SeventiesWreckers

    SeventiesWreckers Load Bearing Wall

    I've read about this before, about a year ago I believe. It makes sense I suppose. So rather than try to prove the findings wrong, I just avoid rechambering unfired rounds over & over. It's not really what I would call "common knowledge", but if you Glock Kabooms you'll run across it.
     
  5. I think its paranoia.




    That said i may chamber twice tops then it gets fired.
     
  6. Interesting read. I my self sleep with my glock loaded on the night stand by me. When I wake up (before I go to work) I will rack the slide back ejecting the round in the chamber then drop my mag. I will then pick up the round that was ejected and put it back into the mag making it the first round once again.

    Every now and then I will take that one round with me to the range and shoot it off. So far they have not giving me any troubles. Knock on wood. Just remember if you pull the trigger and it doesn't shoot, take a big step to the left or right and rack the slide and you should be good to go. So I have been reading.
     
  7. jonm61

    jonm61 New Member

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    It's been discussed for several years now. There are pictures of rounds that have been set back by repeated chambering. Generally, a properly crimped round will not set back from this, but if the ammo maker failed to crimp the round properly...

    Keep an eye on your rounds. Compare them and if one is a little shorter, shoot it off. If it's a lot shorter, dispose of it without shooting it. If you have a caliper and can measure the OAL, that's the best thing, but it takes a visible to the naked eye set back to be an issue.


    Why? :confused: I can't think of any purpose this could serve.
     
  8. I do this cause I don't like to leave my firearms loaded when I am not at home. I live alone and I cant CC so I legally can't leave my property with a loaded firearm.

    What are you thinking? Since you asked. I all ways have an ear open to learn more.
     
  9. jonm61

    jonm61 New Member

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    Ok, well, that makes sense. I should've noted the "Central Illinois". :) Though, I've never really had a problem with leaving a loaded gun home, as long as it was locked up. I used to alternate between a dedicated nightstand gun and my carry gun. When I was ready to leave for work, the nightstand gun went in the safe and the carry gun came out. Back when they were the only two guns I had, I just had a small safe that would fit on a closet shelf. It was in the hall closet and behind some stuff that was quick and easy to slide to the side to get to the safe, and that a burglar wouldn't likely bother moving because of what it was and what was around it on the shelf.

    Anyone who is going to be unloading and chambering rounds regularly, pick up, at least, a cheap digital caliper and measure your rounds frequently. I picked up one of these as my "starter". http://www.harborfreight.com/6-inch-composite-fractional-digital-caliper-99639.html They have one that's only $8.99 right now as well.
     
  10. SquadCapt4

    SquadCapt4 New Member

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    Just another reason I like this group. I learn something new all the time. I have followed the practice of unloading and reloading the same two rounds every time I do draw or dry fire practice. Think I'll be firing off my carry loads next time I hit the range and more careful how I cycle through ammo now. With three mags to cycle through, SSS shouldn't be a SHTF problem. Thanks for sharing this.
     
  11. GunnerGSP

    GunnerGSP Active Member

    Interesting replies so far...learning about a few things I had not thought of before.
     
  12. This is a great thread! May as well ask to see if anyone does (or at least tried) this. In addition to your usual SD ammo, get a box of less expensive hollow point ammo, and use that stuff only as your chambered round. At least this way, the only ammo that is getting set back is the less expensive stuff, and the rest of the magazine is full of the higher quality ammo. Anyone done this? How did it work for you if you have done this?
     
  13. alba666

    alba666 New Member

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    I like to clean the Glocks I CCW at least once a quarter. I find carry guns accumulate junk in weird places. When I do this, I'll unload all my magazines so I can check for bullet setback when I reload the magazines.
     
  14. GunnerGSP

    GunnerGSP Active Member

    It's funny you mention this, because I thought of a system similar to what you outline above. I do need to unload on a routine basis. Maybe this is a bad idea or over-thinking things, but...

    Top the mag with and then chamber a Winchester Ranger JHP (a less expensive but decent round). Then fill the mag with the preferred PD round.

    Once home, or wherever you need to unload, take the ejected round and put it back in the box noting which rounds have been chambered and which ones have not. Cycle through the box and then shoot it.

    I just can't see excessive shooting/practicing with PD ammo that in some cases exceeds $1 per round. I do realize one should become familiar with their PD round and practice with it...making sure it shoots and cycles properly and so on. But I want my box of PD ammo to last a while (just not forever of course). Shoot some, save some.
     
  15. jonm61

    jonm61 New Member

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    If you're going to do that, you might as well just use FMJ. The chances of having a problem with current, high quality, HPs is so slim that it's just not worth doing anything special. Keep an eye on your rounds and act accordingly if you see something wrong.
     
  16. GunnerGSP

    GunnerGSP Active Member

    It was just a thought...not set in stone really.

    Thanks for the comments.