A few newbie questions

This is a discussion on A few newbie questions within the General Firearm Discussion forums, part of the Related Topics category; Sorry for the newbie question, but could someone please explain this to me? Originally Posted by GlockFaq.com Why is it so dangerous to re-chamber the ...

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Thread: A few newbie questions

  1. #1
    New Member Array Gentoo's Avatar
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    A few newbie questions

    Sorry for the newbie question, but could someone please explain this to me?

    Quote Originally Posted by GlockFaq.com
    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.
    Are they saying not to put a magazine in, chamber a round, then eject it and put it back? Also, what it OAL? Finally, why should you not carry ammo for more than three months?

    Thanks again.

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  3. #2
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    OAL = Over All Length

    Bullets are just crimped on the top of the case. What happens when you cycle a cartridge is that the bullet gets pushed into the case because the crimps aren't that tight. This has two negative effects. One is it can fail to properly load into your chamber because it cannot engage the ramp that pushes it into position.

    The second is it can cause higher than normal pressures when the powder burns. If it is significantly higher pressure damage to the gun and failure of the gun can occur. The reference to the KABOOM.

    So yes, loading and reloading the same cartridges is not a good thing in semi-autos.

    If you carry your ammo all the time it is assumed that it will go through heating and cooling cycles do to varying environments. This can cause condensation inside the case and render the powder inert or reduce the amount that can burn etc. It is a generally accepted practice to rotate ammunition every three months. From a more practical standpoint you shouldn't go more than three months without shooting the ammo you carry so you can practice your shooting skills with your carry ammo.

    My cynical side says that the ammo companies just want you to buy more of the expensive defensive ammo to promote sales. However I'll go with the minimum practice interval of 90 days.
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  4. #3
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    If you constantly load unload, the top round (may) get pushed deeper in the case(setback) causing excessive pressures when fired. OAL =overall cartridge length used to measure during reloading). I don't see how 3 months can cause ammo to go bad. i have shot ammo from 1945 and older. while I would replace my ammo possibly yearly, I don't see 3 months being needed.
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    Since Hot Guns posted in your initial thread - which I will delete as you found you'd gotten in wrong forum - here it is -

    Quote Originally Posted by HotGuns
    OAL means over all length.
    This is the length of the bullet measured from the very tip of the bullet to the end of the rim on the case.

    Three months is an arbitrary figure. If one loads and unloads his weapon a couple of times a day on the average and cycles though his magazines, it would ensure that each bullet would'nt have been cycled though the chamber more than a couple of times.

    What happens is when a bullet is cycled into the chamber, it may smack the end of the feed ramp hard enough to set the bullet further in the case than it is meant to be. With semi auto pistols, there is usally a range of length on the bullet that they can successfully feed without any problems. If you shorten this length up, the bullet may be too far in the case to make an easy transition up the feed ramp and into the chamber. If its too short, it just jams and wont feed. The spring pressure from the slide will hammer it into the feed ramp and its enough to make it even shorter.

    In as defensive carry gun, the last thing you need is a jammed up pistol. Its a good idea to shoot your gun at least that often anyway just to keep in practice. Shooting is a perishable skill. It takes practice to stay good. Shooting every three months keep you in practice and ensures that no "short" rounds will jam up.
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    New Member Array Gentoo's Avatar
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    OK I think I understand now. Is it OK to leave ammo in magazines for a while, or should they be kept unloaded?

    Also, the 90 days theory applies only to ammo carried with you, right? The ammo in my desk and closet is OK for long term storage correct?

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    I have had no issues w/ spring wear in any of my loaded mags. Stored ammo should be fine.
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    Senior Member Array hsuCowboy98's Avatar
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    I just shot some 8mm Mauser ammo from 1923 this morning in fact. Dont know what that means, but that old stuff still shoots, not that Id trust it.

    Everyone else covered the rest...so I had to throw that random fact in.
    Fear No Evil.

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    That is some real old 8mm - hope you did the post corrosive ammo clean up properly
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    VIP Member Array Bud White's Avatar
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    It is fine to leave ammo loaded in the mag's i see bullet setback was all ready covered so i won't go into that again .

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    One additional note also.

    Repeatedly chambering & unchambering of the same rounds sometimes causes actual physical damage to the cartridge cases kicking up tiny burrs & creating tiny cuts/gouges to the cartridge case from the extractor and sharp mag feed lips.

    It's possible for those "chewed up" cartridges to cause possible feed or function problems when actually needed for self defense.

    I have no kids in my home so I usually leave my daily carry firearm loaded & the chambered round stays chambered.

    The magazine stays in & the firearm loaded until general maintenance and routine cleaning time.

    Since me & my Wife treat ALWAYS all firearms as if they are loaded then having one STAY loaded is never a problem for us.

    We are adults and we are conditioned to treat all guns as HOT/Loaded until such time as a physical & visual check proves that ANY & EVERY firearm is unloaded.

    I personally have No Reason to Unload my Carry Firearm when I get home from a day or night of being out and about.

    My Gun does not know if it's sitting at home or still outside roaming around.

    My magazines do not need to "rest" and my gun never gets tired of being loaded.

  12. #11
    Distinguished Member Array dimmak's Avatar
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    Quote Originally Posted by QKShooter
    I have no kids in my home so I usually leave my daily carry firearm loaded & the chambered round stays chambered.
    I have 2 kids in the home and that is why mine remain loaded and chambered at all times....
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