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Thread: Flush fit 7rd mags for full size 1911

  1. #11
    Join Date
    Mar 2010
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    Quote Originally Posted by Steve_in_Allentown View Post
    One thing I found that I did not like about CMI was their spotty quality control which tainted their performance on occasion. Once I identified the potential failure points and developed a method for inspecting for and correcting them, I've not had a single failure since.
    Any details you can share? Photos/measurements/pointers would be helpful.

  2. #12
    Join Date
    Dec 2019
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    Quote Originally Posted by Wildcat View Post
    Any details you can share? Photos/measurements/pointers would be helpful.
    Sure but remember you asked for it. Rather than rewrite a bunch of posts I've written on the subject I'm going to take the easy way out and simply copy & paste them here. They may be a little out of context since some of them are replies to questions but you'll get the jist of them. This is not an exhaustive compilation - just a sampling.

    Bottom line up front: Potential areas of concern include burrs near the top of the mag tube, forward follower legs that need to be bent slightly backward, locating tabs on either side of the follower that need to be sanded down a touch, tight spots inside the tube that need to be sanded, weak mag springs.

    A relatively small percentage of mags may have one or more of the potential issues. The mags I got from Ed Brown were the worst but I obtained them very early in their exchange program. More recent reports indicate this has been rectified. A couple from Top Gun had issues. None from Thunder Mountain Custom had any issues.

    The potential areas of concern may be scary for some folks. Rest assured the fixes are quick and easy. The resulting mag will run 100% until the spring wears out (I replace these with Tripp springs) or the feed lips spread (at which point I throw the mag away).

    18th August 2012

    Check-Mate magazine issues, cause, and customer service

    I have put tens of thousands of rounds through McCormick 8 round magazines over the years with no issues. But they would contact the ejector on a couple of pistols and although I have relieved many ejectors to avoid contact with magazine bodies these two pistols had too much ejector contact for me to be comfortable removing metal from them. So, i began to look at other magazines in a quest to find one that would solve this particular problem with these two pistols.

    I tried the Tripp 8 rounders and the Check-Mate extended tube 8 rounders. Eureka! I love the Tripps. I love the Check-Mates. The Check-Mates are different in that they use hybrid feed lips which allow for very smooth feeding and they have the little "pimple" on top of the follower to help prevent inertia feeds plus they're less expensive than the Tripps.

    I bought a batch of Check-Mates a year ago and began using them as I was completing work on a Springfield 5" this past summer. During a range session I was experiencing multiple inertia feeds which had me completely flumoxed. I could not for the life of me figure out what was causing these malfunctions until i disassembled the magazines and found that the followers were sticking within the tubes.

    Normally, the follower should move freely up and down the length of the tube due to its own weight and gravity (obviously the spring has to be removed).

    I called Check-Mate and was asked to return the magazines to them. Check-Mate is not a tiny company, 1911 magazines are not their only product, and I'm just a single consumer. Nevertheless, the president of the company got personally involved and within days I had brand new, fully functional replacements in hand.

    The president and I swapped several e-mails in which he explained that the problem was due to an error in the heat treatment of the tubes during the manufacturing process.

    Bottom line: major kudos to Check-Mate and their commitment to customer service.


    Jun 3, 2018

    Testing Methodology

    Cartridges tested

    PPU 230gr FMJ
    Federal Hydra-Shok JHP
    Barnes XTAC 185gr JHP
    Corbon 200gr JHP
    Corbon Pow'RBall 165gr
    Remington Golden Saber 185gr JHP
    Remington Golden Saber 230gr JHP
    Hornady ZMAX 185gr JHP
    Hornady FTX Critical Defense 186gr JHP

    Handload Precision Bullets 200gr HG68 style SWC

    Magazines tested

    Officer length

    MagPack 7rnd
    Checkmate CM45-7C-B
    Colt branded Checkmate CM45-7C-S-H
    Tripp Cobra 7R-45-RO
    Tripp Cobra 8R-45-RG with extended spring plate trimmed for use in Officer frame

    Government length

    McCormick PowerMag stainless
    McCormick PowerMag blue
    McCormick PowerMag stainless with Tripp Super 7 upgrade kit
    McCormick PowerMag blue with Tripp Super 7 upgrade kit
    Checkmate CM45-7-B-GI
    Checkmate CM45-7-B-H-CMF
    Checkmate CM45-7-S-H-CMF
    Checkmate CM45-8-S-H-EXT
    Checkmate CM45-8-S-H-EXT with Tripp Super 7 upgrade kit
    Tripp Cobra 8R-45-RG
    Wilson 47D

    Pistols tested

    All frame ramps verified to be 31.5 (except ramped barrel which I lack the correct tools or imagination to measure).

    Colt Government
    Colt Officer
    Colt CCO – steel frame ramp insert
    Elite Warrior Commander – steel frame ramp insert
    Springfield 1911-A1 5”
    Springfield 1911-A1 LW 5” – Briley ramped barrel


    Generally speaking across all pistols and ammo the Checkmate CM45-8-S-H-EXT proved to be the smoothest feeding. There were exceptions the most notable of which was the Pow'RBall in the ramped barrel. This combination of cartridge, pistol, and magazine simply did not work.

    The ramped barrel Springfield was the pickiest in terms of which ammo it liked. Its favorite cartridge was the Corbon 200gr JHP followed by the Golden Saber 185gr JHP both of which fed incredibly smoothly across a range of magazines.

    The Colt Government was the least pickiest followed by the Springfield 1911-A1 5” both of which fed incredibly smoothly across a range of ammo and magazines.

    General comments

    Some years ago when I bought my first Checkmate extended 8 rnd mag with hybrid feed lips I had noted the smoothness of feeding but paid little attention because I had no particular problems with any of my mags. I ran McCormick PowerMags in IDPA matches and never had a problem. Then one day with a new pistol the Checkmate exhibited inertia feeds which caused me to focus on this mag to trace the source of the problem. I didn’t want to give up on it because the smoothness of the feeding was so noteworthy. So, I dropped in a Tripp MSC 14C 042 magazine spring and the inertia feeds disappeared.


    Jan 19, 2019

    Slide failure to lock open on an empty magazine - new cause

    This subject has been addressed many times and solutions include such things as replacing the magazine spring, bending the engagement tab on the follower outward, replacing the slide stop, using hotter ammo, replacing the recoil spring with a lighter one, and others.

    Today I discovered a new-to-me reason for this kind of malfunction.

    I had multiple failures-to-lock-open with three specific magazines. I chalked it up to cold weather and/or a weak powder charge. But this just didn't make sense to me since this pistol has had thousands of rounds through it with many magazine brands and has always run 100%.

    When I got home I disassembled the three problem mags and remembered this was their first trip to the range. I put the followers back in and did my usual teeter totter test which they all passed. Then I put the mag springs back in with just enough tension to provide some resistance to the follower. I pushed each follower down and slowly let the springs push them back up and each follower got stuck just before coming all the way up into contact with the feedlips.

    After a few more diagnosics I determined there was a burr left over from the manufacturing process on the inside surface of each mag tube in just the right place to prevent the follower from coming into contact with the slide stop lobe. This did not affect the feeding of the last round in the mags.

    The fix was removing the burrs. Another trip to the range and the mags ran faultlessly.

    See the pictures below.


    Jan 20, 2019

    Here's some more detail to show where the burr occurred and how it interacted with the follower.

    "A" and "B" in the picture below are pointing at different areas of the tab on the mag follower that makes contact with the slide stop lobe to push it up after the last round in the magazine is sent down range.

    "A" indicates the very top surface of that tab. This is what actually contacts the underside of the slide stop lobe. If you look very carefully, you can see this surface looks a little different than the rest of the follower. That's because the follower wasn't cleaned after shooting and the powder residue has been worn away in that spot because of repeated contact with the slide stop lobe. This picture was taken after I'd gotten rid of the burr and the follower was now doing its job of holding the slide open.

    "B" indicates the very edge of the tab where it had been running into the burr. Once again, a close examination will reveal a very small area where the bluing had been worn away by the burr.

    "C" in the picture below shows the exact spot where the burr and the follower met. When this happened the follower would stick which meant the follower tab couldn't push the slide stop up to engage the slide. Note how the follower is not fully up against the feedlips.

    The follower had not been stopped by the burr until after the last round had been chambered. At that time the follower rose up in the tube but was still being slightly depressed by the disconnector rail. When the slide moved rearward and the disconnector rail was no longer depressing the follower, the follower moved up enough to hit the burr which stopped it in the position shown in the picture.


    May 21, 2019

    Inertia feeds and false-positives

    I was reminded again today during a trip to the range that magazine followers that get stuck somewhere in their travel from the bottom of the mag to the top can cause malfunctions that you'd swear were inertia feeds. I had one today where there was a live round in the chamber and another one jammed underneath it. Classic inertia feed, right?

    That was my first thought until I disassembled the mag and found the follower was sticking in the tube at one spot. Quick work adjusting the forward follower leg with a pair of pliars and no more problems.

    This is what I call a false-positive diagnosis. I just knew it was a classic inertia feed gremlin and I knew it was going to be a hassle trying to track down the cause. But I was wrong. I guess technically it was an inertia feed but the cause had nothing to do with the usual suspects (recoil spring, firing pin stop, oil inside the mag, or invisible gremlins).


    May 27, 2019
    . . . but to me ... CheckMate hybrid feed lips = inertial feed
    Tsk, tsk, tsk. Once upon a time I thought the same thing but discovered it wasn't the design of the feed lips that was the problem. It was weak springs or, more commonly, out-of-spec followers. In my estimation the out-of-spec followers were a result of poor manufacturing quality control not poor design. Once I tweaked them so that they moved freely through the length of the tube and replaced the springs as needed the magazines have been flawless.

    Would I rather not have to tweak the followers? Sure. But these mags feed incredibly smoothly so I don't mind doing a little work to get them to run 100%.

    I've tested them against Wilson, Tripp, McCormick, Metalform, and other mags. I'm now a true believer. I'd have to review my test notes but I don't recall a single instance where any of the other mags fed smoother than the CMI using any combination of ammo and pistol. In fact, I was surprised at how clunky the other mags fed. I could feel the kerchunk as the cartridges made their way through the feeding cycle.

    To each his own and thanks to the wonder of a free market captialist economy we have many different brands from which to choose.


    Jun 15, 2019

    I posted this earlier but thought I'd relate my most recent experience with the EB branded CMI mags again.

    I recently swapped another 20 old mags for 15 EB 8rnd and 5 EB 7rnd mags. Half of the 8rnd mags and 1 of the 7rnd mags had sticking followers which I fixed using elbow grease, 400 grit sandpaper, and a little bending of the forward follower leg. One of the 7rnd mags had a horribly bent spring that I could not fix.

    I communicated with John May <> at EB and advised him of all the above complete with detailed pictures of the problems and how I went about fixing them. He said he'd send me a replacement spring when a new batch arrives.

    A line from one of his e-mails to me: "I will share this info with our guys and thanks for keeping me in the loop. Seems as stiff as we keep quality control some slip by. Working on some more improvements now."

    I can say that I've not yet run into a Checkmate 8rnd extended tube mag that has failed to drop free from any 1911 I have. Just luck I imagine.

  3. #13
    Join Date
    Sep 2011
    Eastern PA
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    1 (100%)
    Quote Originally Posted by Steve_in_Allentown View Post
    I ran McCormick exclusively during my IDPA competition days and never had a problem.

    Then one day when I apparently had nothing better to do I began experimenting with all the different brands of magazines I had on hand, all the various types of factory ammo, and all the different 1911s on the bench. That morphed into a 3 day marathon of testing every combination of magazine, ammo, and pistol. During that test I stuffed somewhere around 5,000 rounds of ammo into magazines and ended up with a seriously sore thumb at the end of it.

    Without going into all the details, the result was I traded away nearly all my McCormick, Tripp, Wilson, etc. mags for 8 round, extended tube, hybrid feed lip Checkmates. There may come a time when I discover a better mag but for now they are my go-to-war choice.

    One thing I found that I did not like about CMI was their spotty quality control which tainted their performance on occasion. Once I identified the potential failure points and developed a method for inspecting for and correcting them, I've not had a single failure since. I consider the small time investment involved in this to be well worth it.
    Do you have a local source for these mags? Or one online?

  4. #14
    Join Date
    Dec 2019
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    Quote Originally Posted by pag23 View Post
    Do you have a local source for these mags? Or one online?
    I prefer dealing with Thunder Mountain Custom. Mike offers the best prices, customer service, and shipping. Tell him I sent you.

  5. #15
    Join Date
    Feb 2009
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    Quote Originally Posted by Wildcat View Post
    Might also look at Metalform.

    Brownells offered some 7-round mags that looked like they were made by Metalform for Brownells; or at least copied the Metalform follower. I bought several of them to replace some craptastic gun-show-specials that were knocking around in my gun bag. It doesn't look like the Brownells 7-rounders are available any more (which is disappointing because they work fine) but Metalform 7-rounders are, and are reasonably priced.
    +1 for metal form. ACT is another one to try as well, I have a few and they have been fine, at least in single stack .45 anyway.

  6. #16
    Join Date
    Sep 2008
    Feedback Score
    3 (100%)
    The good:

    Ed Brown

    The bad:

    Pro Mag

    The ugly:

    No name gun show cheapie

  7. #17
    Join Date
    Feb 2013
    Feedback Score
    3 (100%)
    Quote Originally Posted by Steve_in_Allentown View Post
    I prefer dealing with Thunder Mountain Custom. Mike offers the best prices, customer service, and shipping. Tell him I sent you.
    Thank you for the link. I will be buying from them.
    Train 2 Win

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