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Thread: bullet setback in case

  1. #1
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    bullet setback in case

    This really isn't a question or comment about my r1 commander. or any other 1911 I currently own or have owned in the past. Right now that is just my Remington and a Taurus PT-1911 with rail. It's about ammunition. Yesterday my wife and I did some target shooting and I ran a good bit of ammo through my .45 pistols and as usual ended up with four or five rounds of 230 fmj that the bullet had set back in the case on chambering. These were found when ejecting them unfired from the chambers of the guns. The ammo used was Winchester 230 target and range loads, along with Federal Hydrashock.

    I have owned at least a dozen 1911 pistols over the years, mostly Colts till they priced themselves out of my market, and fired thousands upon thousands of rounds of ammo out of them of all makes and brands, and have fought this problem for years. Does ANYBODY make a 230 hardball round that doesn't set back in the case when chambering? Even the best of wht I have used can only be chambered once without setting back on the second chambering or at best the third. I have a desk drawer full of setback rounds obtained from unchambering the pistols for cleaning. I need help.

  2. #2
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    Personally, if you are getting visible bullet set back, you are almost certainly getting increased pressure.
    Please supply pictures.
    Is it happening with different magazines, different guns?
    I have never had that happen with any of my 1911s. Get the gun checked by a gunsmith.
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    MuyModesto (17th October 2018)


  3. #3
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    Hi noylj, thanks for replying. As I said above I have been fighting this problem for years and in every 1911 I have ever owned. Seven of those were Colt government models, series 70 and 80, a stainless Colt Commander, an old ww-2 military Colt, two Remingtons, one a military model, an auto ordnance, and a Taurus Pt-1911. I guess I have magazines from everybody who makes them but I prefer Colt 8 round factory mags with Wolf 5% overpower springs installed. I am amazed you have never encountered this problem, every single person I know who owns a 1911 of any type has this same problem with theirs. I polish the feed ramps on most of my 1911 pistols and have taken a couple to my gunsmith and had him work on them but it really doesn't make much improvement in the bullet setback issue. Some but not much. I used to reload and got to where I would put some sealer on the bullets before seating them and that did help some also but I moved a while back and have not set my reloading stuff back up since. What I am looking for is a factory load which has sealer or something to help hold the bullet from setting back after a couple of chamberings. Lots of factory loads will set back on the first chambering at least one in ten rounds, which I found by ejecting live rounds after they chambered under live fire. Not in just one gun, but in a wide variety of high quality 1911 pistols using high quality mags with fresh springs installed and the feed ramps polished. A friend of mine said the military used to use sealer on their 45 ACP ammo and the batches he had tried years ago were far better at not setting back than the factory ammo we have available now.

  4. #4
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    After monkeying around with bullet setback for several years my conclusion is that there is only one brand of commercial 45 Auto ammunition that doesn't suffer setback upon chambering in a 1911 and it tops the list below:



    And the reason the PMC I tested suffered no setback is because its bullets are sealed to the case with some sort of waterproofing agent - just like most military ammunition.

    Based on all the tests done I'd have to conclude that setback to varying degrees is normal and setback varies a lot with the number of rounds in the magazine:

    The first couple of rounds fed from a full magazine will get set back the most because these rounds hit down low on the frame feed ramp.
    The last few rounds fed from the magazine get set back the least because they either hit the frame feed ramp up toward its top or may not hit the feed ramp at all.

    Furthermore, there's nothing at all that can be done to prevent the fist few rounds from a full magazine from hitting the feed ramp down low. That's because it's all a result of the amount of nose support the top round gets from the rounds below, as shown below:



    And the only - repeat - ONLY way to avoid having a gap under the nose of the top round of a full 1911 magazine (and avoid any chance of bullet setback) is to have a magazine in which all the rounds are directly above the one below. And that would involve changing the 1911 magazine well angle from 17 to 0 - or straight up and down.

    While it's certainly true that bullet setback will cause an increase in chamber pressure, that increase in chamber pressure doesn't seem to be a problem (unless you're in the 1911 Benchrest crowd). I've also concluded that bullet setback becomes an issue only when it cause a 1911 to jam. And it can. Following standard loading procedures and using factory components I've even loaded up some test rounds that are just about guaranteed to make any 1911 jam with the bullet nose planted firmly on the feed ramp - all due to too much bullet setback.
    When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. [Lord Kelvin]

  5. #5
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    I know many years ago when there were far less options of which brass to use I used to sort out my fired brass before reloading. I found Winchester and Federal had thicker brass but when I reloaded Remington brass I had to readjust my reloading die to get a good taper crimp. This is when I reloaded FMJ bullets. The lead bullets I cast were not such a problem after I sized and lubed them.
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    MuyModesto (24th October 2018)


  6. #6
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    I think the reason our home cast and sized lead bullets have less setback than FMJ or plated ones is that they're simply a little bigger in OD. I've measured a lot of factory FMJ and plated component bullets and they measure in the 0.4505 to 0.4515 range. Don't recall ever measuring one at 0.4520" OD. Most good 45 Auto bullet sizing/lubing dies will turn out one with an OD of 0.452. I even had one specially made to size them to 0.453" OD for use in thin brass. And I think even 0.0005" makes a difference when it comes to the cases grip on the bullet.

    For my cast lead handloads, something is wrong if I don't see a bulge in the case in the vicinity of the base of the bullet. The cases grip on the bullet is at its very maximum just after the bullet is seated and the bullet has stretched the case wall circumferentially. Furthermore, anything done to the case after the bullet is seated will - on no uncertain terms - reduce the cases grip on the bullet. Anything. And that includes simply removing any remaining case mouth flare to straighten the case mouth.
    When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. [Lord Kelvin]
    Last edited by niemi24s; 17th October 2018 at 23:07.


  7. #7
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    Thanks niemi, that is exactly the information I was looking for. I'm going to grab a few boxes of PMC and give them a try, and may finally get around to setting my reloading equipment back up too. I lost my right leg below the knee a little over a year ago (blood clots) and it shut me down on everything until recently. I'm finally getting better and able to walk some on my prosthetic leg but learning to shoot again at the level I used to is really tough. One thing I should say, at our shooting session the other day I tested some Federal Hydrashok, which I routinely carry in my Glock 19 9mm and was totally surprised to find that over 50% of the bullets set back on the first chambering, some of them by a quarter of an inch. In fact I took the remaining live rounds and discarded them and will not be buying any more. I tested them in my PT 1911 which has a factory recoil spring and polished feed ramp, but did not run them through my Remington R1 Commander.

  8. #8
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    Most of the bullet set-back you are measuring is insignificant. Serious bullet set-back is 0.100" and more, where pressure will really shoot up and guns blow up.
    I simply have no idea why your gun(s) have this issue, other than the rounds slamming into the feed ramp. If you ease the slide to slowly feed the round into the barrel, does it stop against the feed ramp at all? Can your 1911s feed empty sized cases (all my 1911s can).
    If your magazines have the feed lip running the full length, that could cause the rounds to be released to late. Modern magazines have lips that only go about -⅔ of the way across.
    See:
    Attached Images Attached Images
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    MuyModesto (24th October 2018)


  9. #9
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    Quote Originally Posted by niemi24s View Post
    After monkeying around with bullet setback for several years my conclusion is that there is only one brand of commercial 45 Auto ammunition that doesn't suffer setback upon chambering in a 1911 and it tops the list below:




    And the only - repeat - ONLY way to avoid having a gap under the nose of the top round of a full 1911 magazine (and avoid any chance of bullet setback) is to have a magazine in which all the rounds are directly above the one below. And that would involve changing the 1911 magazine well angle from 17 to 0 - or straight up and down.

    While it's certainly true that bullet setback will cause an increase in chamber pressure, that increase in chamber pressure doesn't seem to be a problem (unless you're in the 1911 Benchrest crowd). I've also concluded that bullet setback becomes an issue only when it cause a 1911 to jam. And it can. Following standard loading procedures and using factory components I've even loaded up some test rounds that are just about guaranteed to make any 1911 jam with the bullet nose planted firmly on the feed ramp - all due to too much bullet setback.
    Even with a perfectly straight magazine you are likely to get some setback.

    Loading a new round into the chamber is rather quick and somewhat violent thing.

    They all hit the feed ramp and are deflected upward towards the chamber.

    It has little to do with support of the shell by the one below it.

    I have a few .45 ACP guns that use straight stick magazines.

    They all set back to some degree.

    Some man7ufactuers tend to use slightly thinner brass that reduces case neck tension.

    It is that slight interference fit of the bullet into the shell that stretches the brass a few
    thousands of an inch in diameter that results in adequate neck tension to try and reduce setback.

    The hardness of the brass (temper) is also a significant factor.
    Dead soft brass has very little tension produced by stretching.
    As the brass gets work hardened the neck tension first increases, and then as the
    brass gets excessively hard the neck tension goes back down.

    As someone noted, for the most part it is not an issue until you get into tenths of an inch for the most part.

  10. #10
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    This shows how little you seem to understand just how a 1911 gets a cartridge from its magazine into its chamber:
    Quote Originally Posted by brickeyee View Post
    They all hit the feed ramp and are deflected upward towards the chamber.

    It has little to do with support of the shell by the one below it.
    It has everything to do with the support given the top round in a magazine by the ones below. Do some actual experimenting and see for yourself. Here are the results of my experimenting:



    The following drawing depicts why the top round in a full magazine hits down the lowest on the feed ramp and therefore usually gets set back the most:



    Do you think the bottom round in a full magazine is held down firmly against the follower too?
    When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. [Lord Kelvin]

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