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Thread: Push Feeding w/ Checkmate Mag

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  1. #1
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    Push Feeding w/ Checkmate Mag

    I took my new Caspian Recon to the range today for the first time. I also took 4 Checkmate 8 round extended tube magazines (hybrid lips), 1 Checkmate 8 round flush-fit magazine (hybrid lips), and 2 Metalform 7 round magazines from an old group buy (wadcutter lips). I've reported elsewhere on this forum the problems I've had with the 8 round flush-fit magazine.

    I shot 200 rounds of Federal HST 230gr hollowpoints and 150 rounds of 230gr FMJ.

    I had two malfunctions, both with the flush fit 8 rounder. In both instances, the slide failed to close the last 1/8", a classic push feed malfunction, and both happened with four rounds left in the magazine. Both also happened feeding the HST hollowpoints.

    This is a picture I took comparing the feed lips of a Checkmate extended tube 8 rounder and the Checkmate flush fit 8 rounder:

    The extended tube mag is on the left and the offending flush fit mag is on the right.

    You can see the the lips of the flush-fit mag flare out at the base. I believe that this is causing the magazine to hold onto the rim of the case. What I think is happening, is that the slide hits the rear of the case and has to overcome the resistance of the indentation, but once the case breaks free, it pops out ahead of the extractor.

    When I cycle the slide slowly by hand I can get it to do this. The other hybrid lipped magazines feed smoothly.

    I would appreciate it if someone could snap some pictures of their Checkmate flush fit magazines (the 7 and 8 rounders both use the same tubes I believe) so I can see if this is a problem with just this one magazine, or if it is common in all of those magazines.

    Thanks.

  2. #2
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    Tom, no picture but...

    my 7 rnd, hybrid lip flush fit welded base looks like the magazine you have pictured on the right. the corner of the feed lip is angled where it begins from the tube, not rounded.

    however the feed lips are not curving in slightly at the back of the magazine like yours appears to be. where they take off toward the taper at an angle the line is a straight line from that point, not rounded.

    hope that helps, if not let me know and I will try to take a picture later.

  3. #3
    Join Date
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    Feed lips are bad on the magazine on the right. They appear to be spread or mis-formed in some manner. Is this a new magazine?
    "The 1911 was the design, given by God to us through John M. Browning, that represents the epitome of what a killing tool needs to be. It was true in 1911 and it's true now." - Col. Robert Coates commanding, U.S. Marine Corp Special Operations Command Detachment 1 (DET 1)

  4. #4
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    Generally, if you are experiencing a push-feed, it will take place because the magazine releases the cartridge too early. I agree the magazine on the right looks a bit strange near the back, but I would measure the full length of the feed lips and compare the two...Robert

  5. #5
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    Both of these are 7 round magazines:



    Regards
    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]

  6. #6
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    Maybe I am getting tripped by my understanding of terminology.

    If I got it right:

    The 1911 system has control of the ctg from the mag through the ejection process.

    Push feed happens when control is lost. The round is chambered and the momentum of the slide forces the extractor to 'snap' over the chambered case rim.

    Either way, push or control, it ought to work, at least untill the extractor breaks. It ought to go 'bang' when the bang switch is activated.

    Maybe I don't understand it right.

    salty

  7. #7
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    Quote Originally Posted by saltydog
    The 1911 system has control of the ctg from the mag through the ejection process.
    Controlled feed is the operative concept here meaning that during the feeding process, there is never a time when the cartridge is flying free, as usually happens with wadcutter mags. Even in the latter case, the flying cartridge rim has to find its way under the extractor before the slide goes into battery. There is a slightly different understanding of the term as applies to rifle actions.

    The round is chambered and the momentum of the slide forces the extractor to 'snap' over the chambered case rim.
    Sometimes...maybe.

    Either way, push or control, it ought to work
    I would disagree. The 1911 extractor is not designed to snap over the case. The extractor hook will break in a short time, if it is snapping over the rim. That problem was "addressed" by band-aid solutions such as toughstuff, bulletproof, and hardcore, while ignoring the real issue of feed geometry.

    Lazarus
    "Do not fix that which is not broken."

  8. #8
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    Hello Lazirus,

    I 'think' we agree. Terminolgy differs a tad. We'll see...

    When I said that it should work 'at least untill the extractor breaks' could have been stated as 'short term'. It should work, no matter the mag.

    I was just suggestion, not too well made, that when 'control' goes out the window, stuff can happen.

    Implied, kinda/sorta, is the notion that, we should not need to take a micrometer to the mags. If that is necessary, a wheel lock would be just as effective.

    The computer driven machines of today that do the stamping/forming are a bunch better than what was avaialble before. 'Perfection' isn't possible and should not be req'd to make all of the components work.

    You and Tom know a whole bunch more about the 1911 than I. It just seems that a micro examination of the components should not be required.

    sa;ty

  9. #9
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    Thanks for the replies and the pictures.

    Yes, it is a new magazine. I'm glad that it seems that the magazine is the problem - that's an easy fix. The base of the lips don't look like any of my other non-Checkmate magazines either.

    Again, thanks.

  10. #10
    Join Date
    28th December 2006
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    Quote Originally Posted by Tom in Ohio

    I would appreciate it if someone could snap some pictures of their Checkmate flush fit magazines

    Thanks.
    all 7 round flush fit
    Left; Checkmate hybrid
    center; newer Colt OEM with pony logo with "C" and "S" stamped in the corners
    right; older Colt OEM?
    No logo, no there marks other than "COLT 45 AUTO"






    the one on the right is unreliable


    ..L.T.A.

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