1911 - Why is it so hard to seat the magazine and how do I fix it? - Kimber Forum


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Old 06-22-2020, 02:03 PM   #1
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1911 - Why is it so hard to seat the magazine and how do I fix it?

The normal operation of locking any fully loaded magazine into a 1911 pistol with the slide forward should require no more force than that which can be applied by pushing it into place using one thumb.

If a ball peen hammer is needed to lock it into the pistol, you’re going to be at a serious disadvantage if you ever need to perform a reload during a match or on the street.

Ignoring the magazine catch for the time being, there are four major areas that need to be checked to determine why a magazine cannot be easily seated.
  • Spring stacking
  • Base plate contact
  • Ejector contact
  • Slide contact


As shown below, the magazine spring (blue) becomes more and more compressed as more and more rounds are loaded into the magazine. The standard flush fit magazine for use in full length 1911 frames was designed to hold seven .45 cartridges. When it is filled to capacity the coils of the spring will still have space between them. This allows the spring to easily compress more when the column of cartridges is pushed further down when the top round comes into contact with the slide’s disconnector rail (aka the stripper rail) as the magazine is seated.

With the advent of eight round flush fit magazines the issue of hard-to-seat fully loaded magazines has become common. These magazines have no more available internal space than the standard seven round magazine so design compromises had to be made to allow eight rounds to fit into a space designed for seven rounds. This resulted in much less free space between the spring coils to allow for additional compression.

Depending on the geometry of a specific pistol, the spring coils in these flush fit eight round magazines may be forced into hard contact with one another as the top round in the magazine is forcefully pushed up against the disconnector rail. This hard contact between the coils creates a solid column of steel which will not compress further. The result is failure-to-seat the full mag as well as shortened spring life. Given the application of enough force over time the magazine base plate may fail.

So, if you have a flush fit 8 round magazines that will not easily seat, only load seven rounds into them. Note that many pistols do not have this issue.

Magazine identification in the picture below from left to right:
  • flush fit 8 round Check-Mate
  • extended 8 round Check-Mate
  • extended 8 round Tripp
  • extended 10 round Check-Mate

Note that the magazine tube of the flush fit Check-Mate does not extend below the frame hence the term “flush fit”.

Each of the three extended magazines in the picture above has a tube that protrudes noticeably below the frame. These magazines have enough room to hold the specified number of rounds without over compressing the spring. These fully loaded magazines can easily be seated using one thumb.

If you want to have more than seven rounds in a magazine, keep it simple and get a magazine that was designed from the ground up to hold the number of rounds you want.


Over insertion of a magazine into a pistol is not good. The result can be a bent / broken ejector or a pistol that is completely locked up and out of the fight.

Over insertion is prevented by one thing in the 1911 design: the nose of the magazine base plate that extends forward of the magazine tube. Pictured below is a magazine that uses a nylon base plate (aka bumper pad). The nose of the base plate (blue arrow) fits into a corresponding cut out in the frame (red arrow).

Depending on the dimensions of a specific pistol and a specific magazine it’s possible that the frame cut out isn’t deep enough to allow the magazine to be seated. If this happens with a flush fit welded base plate magazine, the frame cut out can be deepened with a file.

I have never seen this with a factory pistol. I've only ever seen this with after-market magazine wells that were attached to the pistol.

If this happens with a nylon base plate, the nylon can be filed or sanded down (blue arrow). You’ll know you have a good fit between the magazine base plate and the frame cut out when the empty magazine has a small amount of up and down slop when it’s locked into the pistol.


Contact between magazines and GI ejectors is not possible since that ejector does not extend over the magazine well as you can see in the picture below.

However, this is not uncommon with extended ejectors. Repeatedly slamming a magazine into the pistol without correcting this condition will eventually result in the bending or breaking off of the ejector nose. In the worst cases the magazine will be forced up beside the ejector and be solidly wedged in place. This often requires the use of tools to remove the magazine from the pistol. I have seen this happen too many times during local club IDPA matches.

Picture “A” below shows contact between a fully seated magazine and the ejector nose. Picture “B” shows the same magazine after the ejector was relieved to eliminate the contact. Not shown is the magazine with a cartridge in it. The cartridge was also making contact with the ejector so the ejector was further relieved to eliminate that contact and the clearance seen in "B" was the result.

To determine whether or not there is contact with the ejector remove the magazine catch, remove the slide, push the magazine as high as it will go in the magazine well and hold it there while observing its position relative to the ejector. Repeat the exercise with a cartridge in the magazine. In either case no contact is allowed with the ejector.


In rare instances the right side of the top of the magazine tube ahead of the feed lips may come into contact with the underside of the slide keeping the magazine from easily locking into the pistol or preventing it altogether. I’ve only run into this in certain pistols with the combination of EGW Higher magazine catches and McCormick magazines.

To test for this condition remove the magazine spring and follower, remove the recoil spring, remove the disconnector, and install the magazine catch. Pull the slide all the way to the rear, lock the magazine tube into the pistol, and slowly ease the slide forward while being alert to any indications of contact between the slide and the magazine tube. There should be no contact between the slide and the magazine tube. This condition can be so severe that the slide will not close.

The fix is to not use an EGW Higher mag catch, not use McCormick mags, or file down the magazine’s contact point with the slide. Understand that this is not an indictment of either EGW or McCormick. They are both excellent products but using them together in some pistols may result in unwanted slide/magazine tube contact.

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Old 06-22-2020, 07:25 PM   #2
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Good post.

And is that a Chen magwell? Tell me more. Beautiful work.
Yea. Keep telling yourself that split times don’t matter.
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Old 06-23-2020, 04:48 AM   #3
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I don’t have time right now to finish reading this post but I’m looking forward to reading this later today. Thanks Steve
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Old 06-23-2020, 06:56 AM   #4
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Originally Posted by Mike240 View Post
And is that a Chen magwell? Tell me more. Beautiful work.
Yup, it's a Chen weld-on. Jim Milks (Innovative Custom) welded it on and I did all the grinding, shaping, and finishing.

As a retirement gift to myself I built two 1911s using JEM frames, Caspian slides, mostly EGW small parts, and Chen magwells. I call the pistols "The Twins" since they both use the same parts and are finished with blued slides over hard chrome frames. Really they're fraternal twins since one is a 5" and the other is a 6".

Here are a couple of pics of "The Twins"

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Old 06-23-2020, 10:13 AM   #5
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Very informative post. Love everything about you custom builds except maybe the square trigger guard on the six incher. I might like it better after shooting it. The Stan Chen magwells are very nice, that's what I would buy if I needed a magwell.
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Old 06-23-2020, 11:18 AM   #6
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Originally Posted by 2sharp2 View Post
Love everything . . . except maybe the square trigger guard . . .
Ha! My wife didn't care for it either. My concept was to imitate the cool looking 1911s on the pages of American Handgunner from the early 1980's when I was a young, steely eyed tanker.

The Stan Chen magwells are very nice, that's what I would buy if I needed a magwell.
Honestly, I'm a middle of the pack IDPA competitor and a mag well isn't going to get me in the winner's circle. I just splurged on my retirement gifts. Not surprisingly, these really do make reloads noticeably faster, smoother, and simpler.
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