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Thread: Preventing bullet pushback in defensive ammo

  1. #1
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    Preventing bullet pushback in defensive ammo

    After chambering the same round a few times it's common to see pushback, where the bullet is being pressed farther into the casing, potentially creating dangerous overpressure when fired. Since I don't like to spend 5x the money on Gold Dots for punching holes in paper, and since I dry fire with snap caps fairly regularly, rechambering the same rounds becomes an issue with my CCW.

    As a solution, I've considered easing the slide forward to strip a round off the mag with less force than using the slide stop or slingshotting it. Of course, I'd have to make double sure that my pistol was in full battery after doing this. Would doing this prevent pushback? Would this be considered unsafe, or likely to cause any other problems? Any thoughts?
    Peace is good. Freedom is better.

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    You could:

    Measure them.

    Set the top round or two aside after you no longer feel comfortable carrying them and just shoot one or two off at the range.

    Not a big loss there. Actually measuring them could make you feel more at ease.

    I'm no pro, but what caliber is this? Some higher-pressure loads cause this to be more of an issue, while lower-pressure loads, not so much.

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    Some rounds are made (or at least used to be made) with a ring impressed into the case at the base of the bullet. Check to see if you can find some of those.
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    Suggestions

    1. Don't unload and reload the pistol if you don't have to.

    2. When you must unload the gun, rotate the ejected cartridge to the bottom of the magazine.

    3. Either keep track of the number of times a cartridge has gone up the feed ramp and limit it to two or three trips and/or used an accurate measuring tool to check for setback.

    4. Use the full force of the released slide to chamber live rounds - that's how the pistol was designed to operate.

    5. Setback is of greatest concern with high-pressure rounds, such as .40 S&W and .357 SIG, versus medium-pressure rounds, such as .45 ACP.

  5. #5
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    I always had that problem reloading .45 ACP and .30 carbine.

    For the .45, I had to "double-size" the cases by running them into a .30-06 die just enough to squoonch the case down a little bit more, then bell them out again a wee bit. Pain in the tuchas, but it worked. I never really solved the problem with the .30 Carbine cases.

    I note that in the specs for the .45 ACP as shown in Hatcher's Notebook, the actual drawing shows an "asphaltum" seal between the bullet and the case. Presumably, this helped keep the bullet in place as well.

    1911 Tuner, do you have a comment on this?

    I also routinely pull a bullet from new ammo "just to look at it," and most mil ammo (even for rifles) I've purchased shows some kind of black goo on the bullets --possibly the "asphaltum," whatever that is.

    I've often wondered if there's some kind of commercial substitute for that asphaltum which reloaders could purchase --or some kind of sealant/cement we could use.

    (NOTE: "Glueing" the bullet in will not appreciably increase pressures, because as soon as the pressure builds up,the neck expands, releasing the bullet --nevertheless, I never experimented with using any cement-like substances. Not for "pressure" concerns, but for possible corrosion and bore wear concerns.)

    Terry, 230RN

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    Some cartrigese are designed so that setback is not an issue - my Golden Saber 9mm has never set back no matter how many times I've rechambered.

    Ben

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    Super Glue?
    .
    "The dogs bark, but the caravan moves on"

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    ^ I've thought of that, but as I say, I'd be concerned with whatever combustion products result from a complex compound like that under the pressure and heat of firing.

    As a mental excercise ("gedankexperiment"), the best I could think of was something like model airplane glue, which is cellulose/solvent based and is in fact very similar to the powder itself.

    But I wondered about the solvent therein possibly affecting the powder*, and once the glue started to dry on the mouth portion, the question arose as to how long it would take to dry throughout the cartridge.

    I really think the only tried and true substance I would use would be the asphaltum mentioned above, and I'd have to learn the technology of applying it uniformly, etc. in the hobby reloading situation.

    That is, if I could get some from somewhere.

    I note they use lacquer on the primers of most mil cartridges, but that's applied outside the case, where it would not affect the powder.

    Terry,230RN

    --------
    *
    Like, for example, possibly partially solventing the powder into clumps within the cartridge.

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    Asphaltum:
    a dark bituminous substance that is found in natural beds and is also obtained as a residue in petroleum refining and that consists chiefly of hydrocarbons.

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    I use a simple solution. When I unload I keep the ejected round seperate from the magazine then when it's time to reload I manually load that round into the chamber and release the slide prior to inserting my magazine.
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    1. Don't unload and reload the pistol if you don't have to.
    Sometimes one has to. I teach in Detroit, but can't legally carry in the classroom, so I lock my gun in the car, but take the magazine and round in the chamber with me.

    A sheriff's deputy has told me that guns stolen from cars on campus are a problem, so . . . .
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    I use a simple solution. When I unload I keep the ejected round seperate from the magazine then when it's time to reload I manually load that round into the chamber and release the slide prior to inserting my magazine.
    On some pistols that would eventually lead to a broken extractor.
    .
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  13. #13
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    set back

    the black substance is asphalt.It sole purpus is for waterproofing.If you reload crimp the cases.I crimp my 45s/32/380/38 spec.and all others never had a problem.

  14. #14
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    I tend to shoot up my defensive loads, so that isn't much of a problem -- but I also run defensive loads through a taper crimp die, and give them a good crimp before loading them into the magazine.

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    the black substance is asphalt.It sole purpus is for waterproofing.If you reload crimp the cases.I crimp my 45s/32/380/38 spec.and all others never had a problem
    Fine. Where do you get it and how do you apply it and I've never seen the pushback problem with asphalted military rounds, or with the rounds I used the extra .30-06 die on.

    It's not hard to overdo a crimp on a straight pistol case which headspaces on the mouth. Cartridge goes a wee bit too far into the chamber, and the blow on the primer is lighter and variable, and opening up the crimp against the ledge in the chamber on firing may also result in unwanted "variables." You can crimp into a cannelured round and into lead bullets, but you've got to go real easy with it on mouth-headspaced cartridges, and (a) I don't see many cannelured auto pistol bullets, and (b) in avoiding "overdoing" the crimp, you may not end up with enough crimp to solve the problem. There are, as mentioned, taper-crimping dies available, which don't squoosh the case mouth down too far that the headspacing is lost. I never tried one since the aforementioned .30-06 die worked... although use of that die on .45 ACP cases, as described above, before belling the case mouth, might be considered a variation on the taper crimp die concept.

    The main reason rimmed revolver cartridges are crimped is not to keep the bullet from getting pushed in, but to keep it from getting pulled out under recoil. Lotsa fun when a pulled bullet binds your cylinder and you've got 2-5 live rounds still in the chambers. (Note that I said the "main" reason.)

    Ask not how I know.

    Terry, 230RN
    Last edited by 230RN; November 12th, 2008 at 04:04 PM.

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    When I do an "administrative unloading" to clean or tighten grip screws, etc. I then reload by placing the chamber round back in the chamber, and easing the slide forward until it stops slightly out of battery from the extractor encountering the rim. I then push on the slide until the extractor skips over the rim and the slide is back in battery. Muzzle is pointed safely throughout, of course.

    I am told that in some pistols (1911s with standard extractors--which tend to be a little finicky to begin with--as opposed to the external extractors of the SW 1911s and the Power Extractors of ParaOrdnances) this practice may damage the extractor. So YMMV. But I wouldn't expect much trouble unless you're loading the chamber and then releasing the slide under full spring tension.

    Sounds like USMC-Retired is doing the same. And ZeSpectre has commented on the potential extractor problem it presents for some pistols.

    No set-back with this method, but make sure the cartridge rims do not get chewed up.

  17. #17
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    Some guns, you can lock the slide back, push the round under the extractor hook from the top, then ease the slide down. I've done that a few times with my G23. Easing it down when stripping from the magazine works to prevent/reduce setback too, as long as you don't do it too slowly. The round can jump out from under the extractor if you go too slow.
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    Can't you just crimp a little tighter?

  19. #19
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    Rotate your chambered round.
    Then shoot the ones you've been rotating every once in a while.
    I know this costs a little bit more but at least you'll know they still cycle properly.
    Guns can change over time. Hardball target my still function fine but after a while the hollow points might not.
    Commom sense isn't very common anymore.

  20. #20
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    Quote Originally Posted by Kind of Blued
    I'm no pro, but what caliber is this? Some higher-pressure loads cause this to be more of an issue, while lower-pressure loads, not so much.
    9mm, and my preferred carry round is +P.
    Quote Originally Posted by USMC - Retired
    When I unload I keep the ejected round seperate from the magazine then when it's time to reload I manually load that round into the chamber and release the slide prior to inserting my magazine.
    In considering this, I was always scared of some sort of slamfire, so I didn't do it. Perhaps an unreasonable fear to have?

    Any idea if above would cause problems with an external extractor on a Sig P229?

    Thanks for all the ideas and recommendations.
    Peace is good. Freedom is better.

    "Now now, perfectly symmetrical violence never solved anything." - Futurama

  21. #21
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    In considering this, I was always scared of some sort of slamfire, so I didn't do it. Perhaps an unreasonable fear to have?

    Any idea if above would cause problems with an external extractor on a Sig P229?
    Slamfire is unlikely, but it's gotta be hard on any extractor that's intended for controlled feed (as opposed to push feed), not just internal extractor guns. I've done it once or twice in my Glock just to see if it can be done, and that's about it. Extractor's an important part, don't want to risk damaging it.
    He hit the ground, the sound was splat, his blood went spurting high
    His comrades they were heard to say "a helluva way to die"
    He lay there rolling round in the welter of his gore
    And he ain't gonna jump no more

  22. #22
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    FWIW I just shot 40 rounds of my "carry" ammo the other day. It was four years old, though I haven't been carrying that entire time. I'd usually load it up whenever we went out of town and stayed in a hotel. Maybe reload it again when we got home and stash it in my desk drawer. I'm sure in that 4 years I've had it I managed to chamber at least one of those rounds a good 20 times, and this is .40S&W, probably the most likely to have problems with setback.

    And I shot 'em out of a Glock 23, a good candidate for a kaBOOM.

    No problems.

    We might be worrying a bit too much about this issue. Checking your ammo for bullet setback is prudent, and clearing out the old stuff is good, but I wouldn't obsess over it.

    FWIW that ammo I'd been using as carry ammo for a while? Yeah, six months ago it got slathered in KY personal lubricant. Turns out water based lubricants don't do much to ammo. Not surprising, but good to know!

  23. #23
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    When I reload 9mm and 45acp I put a cannelure on the case at the right place with one of these, and I don't play with live ammo like that.



    http://www.buffaloarms.com/browse.cfm/4,5515.html

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    The problem you describe is quite common--unfortunately, some of the most common causes have nothing to do with the ammunition.

    I will guess that you're talking about a semiautomatic pistol. That's OK, as long as you realize that bullet setback can also occur with regularity in semiautomatic rifles, too.

    The first thing to think about is your magazines. Is the magazine holding the round in the proper position for smooth feeding? You would be surprised at the mags that DON'T. A quick way to tell is if the pistol feeds smoothly, with no hesitation or hiccup when the slide is dropped. Ideally, the round should be positioned so that when the slide moves forward to push the round, the bottom part of the ogive (curved part where the nose transitions back into the bullet shank) contacts the feed ramp first. The round then moves forward, guided into the chamber by the feed ramp. As the round moves forward, it should reach the clearance point of the magazine lips; there, the base of the round cams upward and the rim moves smoothly behind the extractor hook as the pistol goes fully into battery.

    If you feel or hear a "hitch" when chambering the round, check the magazine first.

    Check also to see that you have some good, strong springs in the magazine. Getting that cartridge up into feeding position requires a properly tensioned spring. Finally, clean the inside of the body well, and look at the follower.

    Get a snap cap, put it in the magazine and chamber it slowly. Does the round actually tip forward upon feeding? If so, consider replacing the follower with one that does NOT tip.

    Make sure the feed ramp is clean, too. I clean mine, then polish once every five cleanings with a cotton rag and Simichrome polish.

    Next, look to the extractor. Is it beveled on the bottom--or is it nice and square?

    If it is square, get a small needle file. Radius that bottom edge, behind the hook of the extractor gently. You are not trying to reshape the thing--just round off that inner edge so that it does not hang up on the rim of the cartridge.

    Bottom line--your pistol or rifle should chamber smoothly like nothing was there by air. If it does not, look to the feeding system of the pistol as well as the ammunition.
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  25. #25
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    Yes But...

    I use a simple solution. When I unload I keep the ejected round seperate from the magazine then when it's time to reload I manually load that round into the chamber and release the slide prior to inserting my magazine.
    ...this practice will usually cause "dings" on the rim of the case. If done enough times, this could eventually interfere with reliable extraction.

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