Re-chambering vs direct chambering update 3... - Page 4

Re-chambering vs direct chambering update 3...

This is a discussion on Re-chambering vs direct chambering update 3... within the Defensive Carry Guns forums, part of the Defensive Carry Discussions category; Guys, just for the record, I've built 8 1911s from scratch, I've done all kinds of tuning on Glock triggers, furthermore I'm an engineer and ...

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Thread: Re-chambering vs direct chambering update 3...

  1. #46
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    Guys, just for the record, I've built 8 1911s from scratch, I've done all kinds of tuning on Glock triggers, furthermore I'm an engineer and have had numerous deep discussions about force, momentum, friction, impulse, and energy. So if you want to discuss physics of a gun, I'm your guy. Just so we're on the same page, let's review some FACTS, not "I think", not "It makes sense but I've never tried it", but FACTS.

    Let's first give a little credit to gun manufacturers. Don't you think they know as much about the physics and mechanics of their gun as anyone? In the Beretta 92FS and PX4 owner's manual, they describe the direct chamber loading method as an approved way of loading the chamber. They give no warnings that this is hard on the slide or anything of the such. They describe dropping the slide, not lowering it. Sig described it to me in the same way and I asked three times if that would damage anything, especially the extractor. The answer was an no, with no hesitation.

    There is a bit of difference in slide momentum in direct chambering and mag chambering. The real issue is does that matter at all. But again, the manufacturers are every bit aware of this as we are. The question is, what absorbs the slide momentum? The case or a stop in the gun? As I recall, and I'll try to confirm this tonight, the slide doesn't space or stop on the round, but on a mechanical stop in the gun.

    If there was a difference in impact ON THE ROUND, and I'm not so sure there is, all that means to direct chambering is that we don't have to release the slide from as far back, and direct chambering becomes more gentle than mag stripping. QKS just posted how little motion and hence force/momentum it takes to slip the extractor over the rim of the case. I do it as he described, i.e. I lower the slide to about half its range and then let it go. But let us keep in mind that at least three manufacturers, Sig, Ruger, and Beretta, approve of direct chambering with a full force slide drop.

    Some will have no option because their manufacturer does not approve direct chamber loading, e.g. Glock. But to those of us that carry Sig, Beretta, Ruger, and H&K (using their modified direct chambering method), we have an option. That's not to say that those are the only manufacturers that approve of direct chambering, it's just those are the ones we know right now.

    So here's the options: As some have suggested we SHOULD buy a precision caliper and test all of our rounds for setback. I presume that would mean every SD round we chamber from the mag. I presume it would also be wise to keep up with how many times a round has been chambered from the mag. I presume when we eventually see setback that we buy an inertial bullet puller to adjust the round back to it's original dimension????

    So how many are gonna rush out to buy a caliper? I'm not, well that's not fair for me to say that, I already have a 4 digit 6" caliper and a SS 12" dial caliper, two dial indicators, and a long stroke dial indicator, so I really don't need any more precision measuring equipment. I use them for measuring final cuts etc. on my lathe and milling machine.

    It has also been suggested that we rotate our rounds to minimize multiple chambering of the same round. Let's think about that one for a moment. I return to my car from visiting someone in the hospital and I want to reload my gun. I empty the mag, put the last chambered round in the mag first, being careful to keep track of the order the rounds came out of the mag so I can maintain systematic order. I then leave out the next to last round so I can insert the proper round in the rotation into the mag. I insert the mag, chamber the round, remove the mag, insert the final round and reinsert the mag. Smooth.

    Or I could simply drop the loose round in the chamber, drop the slide from about half it's range, insert the mag, holster and drive off.

    This has been blown way out of proportion. It is depicted by some as a disaster waiting to happen, yet we know of three manufacturers, and that's all we've confirmed at this point, that approve of direct chambering.

    So it's very simple, if your manufacturer approves of direct chambering, you can use it at your option and convenience without being concerned about the method damaging your gun.

    If the manufacturer of your gun does not approve of direct chambering, then you don't have direct chambering as and option - maybe. As QKS has demonstrated, direct chambering doesn't take a lot of slide force, IIRC, he said about an inch and a half slide drop will do it.
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  2. #47
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    This is a follow-up on something I said I'd do, I did it, and here is what I found.

    The question was raised, would direct chambering alter the point of impact (POI).

    Well, my new Sig 220R Carry SAO came in today and I've went to the range this afternoon. This was not a rigorously designed or performed test, but since I shoot at least once a week, I do have 'controls' to compare to.

    Based on past performance, with a Sig 220R DA/SA just last week, I typically can put five rounds through one hole at 3 yards. I know that's close, but I have sound reasons for using that distance that I won't go into unless someone asks me to.

    So today I direct chambered a round, released the slide from about the half way point, and inserted the mag with 4 rounds in it. The second shot went right through the same hole as the first. And I do mean through the same hole, i.e. not touching, not a cloverleaf. I didn't do so well on the next three rounds, but they were touching the hole.

    I did about 12 volleys this way and some results were better than others, but the results are fully comparable to what I've seen in the past. Numerous volleys produced first, second, and third shots through the same hole. My best was shots 1, 2, 4, & 5 through the very same hole. If you didn't know otherwise you would think it was one shot. I messed up the third shot and it went about 3/4" low and slightly to the left.

    While this is by no means exhaustive testing, I saw enough for my satisfaction to say there is no change in the POI. None whatsoever that could be measured.
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  3. #48
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    Chambering rounds over and over is not a gun problem, it is not a magazine problem or an ammunition problem. It is a operator problem. If someone insists on doing this, either from the magazine or by "direct chambering", they're walking on thin ice. Maybe you should obtain a revolver.

  4. #49
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    Quote Originally Posted by Drail View Post
    Chambering rounds over and over is not a gun problem, it is not a magazine problem or an ammunition problem. It is a operator problem. If someone insists on doing this, either from the magazine or by "direct chambering", they're walking on thin ice. Maybe you should obtain a revolver.
    Some people need to unload several times a day , due to legal requirements of entering gun free zones. Your statement is incorrect.


    Thanks for all the research and info Tangle. I have changed my loading practices due to the info you have provided.
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  5. #50
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    It is possible to manufacture rounds that will tolerate this but the manufacturers are not doing this. So if you insist on rechambering over and over you really cannot blame the manufacturer of the weapon or the ammo. If you really need to load and unload this much then a semiauto is not a good choice. The reason for the setback is insufficient case neck tension. The ammo companies either don't intend for people to repeatedly rechamber the same round or don't realize people are doing it. Most semiauto pistols are designed for controlled round feeding from the magazine. If you attempt to chamber rounds over and over then bullet setback will take place. Accept this. If you really need to unload and load multiple times in the course of your day then carry a revolver.

  6. #51
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    Who is blaming the ammo manufacturer? this post is informational, explaining and helping to deal with bullet setback.
    "In matters of style, swim with the current; in matters of principle, stand like a rock." Thomas Jefferson


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  7. #52
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    Here's the concept Drail. A guy wants to visit a friend in the hospital, followed by a trip to the doctor's office for a physical, followed by a visit to the courthouse.

    This person chooses not to handcuff his loaded gun to his car because if the car is stolen he looses his fully loaded gun, somebody bad has his fully loaded gun, handcuff keys are universal, and handcuffs can be cut with an abrasive cut off wheel, and probably a bolt cutter or hack saw; in any event the fully loaded gun falls under the control of a BG. He doesn't want to leave his loaded gun in the glove box, and is in a vehicle without a trunk, e.g. an SUV or Crossover, has no place in the vehicle to securely mount a lock box that won't draw attention to the box or be in the way of passengers.

    So this person has to go three places that he cannot carry his gun. He believes it is prudent to unload the gun and take all ammo and mags with him so if anyone were to steal his car or broke into it and took control of the gun, he has no ammo for it and no mags to put the ammo in. If the BGs are teens looking for a thrill ride, a discovered fully loaded, fully operational gun sets the stage for disaster. It wouldn't take but one or two of these incidents where a teen gets killed or injured by a gun they found in a car to push liability onto the gun owner for reckless endangerment.

    As for rechambering a round from the mag, the rounds will take one or two chamberings before they start to move. From my tests of well over 100 cycles of various guns and ammo, once the bullet moves the first time, it moves a little bit easier the next time. So yeah, all effort should taken to avoid loading a round from the chamber more than once.

    But direct chambering is very much like loading a revolver. There is zero impact on the nose of the bullet and hence nothing to cause setback. The extractor slipping over the rim of the case is not the earthquake event some make it out to be, if you try it, you'll notice it is observably more gentle that chambering from the mag.

    So if there is no setback, what exactly is the problem?
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  8. #53
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    OK, you win.

  9. #54
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    As for rechambering a round from the mag, the rounds will take one or two chamberings before they start to move.
    Probably true of the better stuff. I've seen some factory stuff that would show setback after only one chambering. Not much, but detectable.

    The Blazer Aluminum is especially prone to this, I guess the aluminum cases don't have the same grip that brass does.
    My problem has been the reverse, I've had pistol cartridges get longer in the unfired rnds when used in revolvers.
    Makes sense, especially with a hot load with heavy bullets in a light revolver.

  10. #55
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    Quote Originally Posted by JohnKSa View Post
    Probably true of the better stuff. I've seen some factory stuff that would show setback after only one chambering. Not much, but detectable.

    The Blazer Aluminum is especially prone to this, I guess the aluminum cases don't have the same grip that brass does.Makes sense, especially with a hot load with heavy bullets in a light revolver.
    John,
    What you said is very true, esp., "...I've seen some factory stuff that would show setback after only one chambering. Not much, but detectable." I have too.

    I'm glad you posted that because I'm not sure that was emphasized enough. When I said one or two chamberings from the mag, I meant that as an outer limit, best case scenario.

    What you have stated is the very thing that really concerns me about chambering from the magazine. Some gun/round/caliber combinations are worse than others. Even if a person religiously rotates rounds in the mag(s), as each round is chambered from the mag, it may very well experience that 'not much' you described. It may be detectable, but not noticeable. After every round has been rotated, they start their second time through the chambering from the mag process and get a bit more reset. The danger here is that if the user is comparing round to round instead of actually measuring rounds, they could all look pretty much the same yet all have set back.

    Also, something I had not thought of until your post, is that even if a round has only been chambered once, and it is now in a 'rotated' position in the mag, when that round is chambered to fire it, that's twice it has been chambered. That alone could cause significant increase in pressure, esp. in .40, .357 sig, and 9mm +p & +P+.

    Of course the rounds are subjected to the same forces just by shooting the gun and chambering a round via the gun's cycle. But in the shooting case, it is a one-time/first time chambering and the round is fired before setback can accumulate.
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  11. #56
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    The single issue of possible damage to the extractor in direct, or magazine loading the chamber, depends on how the firearm was designed to chamber a round. Some pistols were designed as "controlled round feed" and some were designed as "push feed". In the single case of the 1911 design, the intent in the design was for the cartridge rim to slide up under the extractor hook as it fed from the magazine. When you direct feed the first round, you cause the extractor to flex around the rim to an extent it was not designed to handle. It will normally accomodate a certain amount of this, but repeated loading in this way will definately weaken the extractor and contribute to premature breaking.

    If someone is not familiar with the differences in "controlled round feed" and "push feed", it would be good to research it, so you can understand the stresses on the extractor.

    I don't mean for this explaination to apply to anything except the 1911, but it is worth noting.

    Best wishes,

  12. #57
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    Well,

    I just got off the phone with SA and was told that there was no approved method for direct chambering a round in the Springfield XD's.
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  13. #58
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    I appreciate that CT-Mike. It's good to know if a specific gun can be direct chambered and which ones cannot be. I think the current list is:

    Direct chamber approved by manufacturer:
    Sig
    Beretta PX4
    Beretta 92FS
    Ruger - I forget the models now, but someone posted them in this thread
    H&K USP - but you must press on the back of the extractor, instead of a free drop

    Cannot direct chamber, or not approved by manufacturer:
    XD
    Glock

    Unknown:
    1911

    Carleb,
    I know of no handguns that use a push feed to load from the magazine. I asked the guy at H&K why Beretta and Ruger allow direct loading and describe it in their manuals. He said that it just depends on the design and operational characteristics of the extractor. H&K uses an eliptical extractor that was not designed for direct chambering and they have seen some damage from direct chambering. He then described how direct chambering was acceptable with the USP by pressing on the back of the extractor.

    As for the 1911 per se, I'm not aware that it is a known fact that direct chambering will damage the extractor. Plus, a number of 1911s have external extractors, and of course ParaOrdnance has a Power Extractor - it is Para that has the power extractor isn't it?

    Have you seen a damaged 1911 extractor due exclusively to direct chambering? How many times did it take and how was it damaged? Would one of the tougher extractors, e.g. I use Wilson Combat tool steel extractors in the eight 1911s I've built, have prevented the problem?

    The reason I ask is that the amount of over-travel a 1911 extractor experiences in sliding over the rim vs under the rim, is only 0.040". I have no concern whatsoever with that small movement. The 1911 extractor falls in the category of a leaf spring. While any spring can be over flexed, the small distance the extractor has to move, 0.040" to slide over the rim of a case is not anywhere near excessive.

    I've recently been involved in a spring compression study for an entirely unrelated application and have found that unless a spring is of really poor quality, i.e. inappropriate steel, or unless the critical stress point is reached, the spring will return to it's orignial length. IMO, this critical stress does not apply to recoil springs and mag springs. They are both long travel, compression springs and when a spring is stressed that much for that many times, for that long, it does have an impact on the spring. OTOH, valve springs operate hundreds of thousands of times and there are few failures.

    My concern is, is the face of the 1911 extractor sloped and positioned in it's free state so that it can freely 'ramp' over the case instead of the end of the extractor striking the back of the case? From what I could see working with my 1911s, the extractor will ramp. But again, if the manufacturer doesn't approve of it, then one is taking on some risk if he uses direct chambering.

    If direct chambering is not approved by the manufacturer for one's particular gun, then he is stuck with loading from the magazine, and making sure he never chambers any round more than once.
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  14. #59
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    Ruger - I forget the models now, but someone posted them in this thread
    I listed the P89 and P95, not because it's an exhaustive list but because I have read the manuals for those models.

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    I'm not 100% certain, but I suspect the Desert Eagle is a push feed. IIRC it has a rotating head bolt.

    Austin

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