10mm Kimber ejection marks, etc. (continuation) ...

[Mike_Fontenot]

(The first part of this discussion was part of the closed "best alternative caliber for the 1911?" thread).

Interestingly, I haven't noticed any more of the marks appear since I've been experimenting with an EGW flat-bottom firing pin stop and a heavier mainspring [...]

How does the firing pin stop affect ejection?

And the mainspring (as opposed to the recoil spring) also matters? (I've got a 20 lb Wolfe recoil spring on mine, in place of the original 18 lb spring).

I also haven't experimented with any other brands of 10mm magazine. For one thing, I want to stick with a flat-bottomed magazine, and many of the alternatives seem to have the extra plastic piece on the bottom. How has your experience with the Wilson been? For my backup magazine, I bought another Kimber (through Midway). It seems almost identical to the one that came with the gun ... logo on the bottom looks VERY slightly different, and the spring has always seemed very slightly weaker to me. But the problem yesterday happened with the original magazine, and I THINK the cartridge that fired right before the lock-back was one of the new Underwoods (and the cartridge that jammed was the other type of Underwood I think), but I'm not sure of that.

[jason41987]

i started the other thread and was actually following along with this.. in case a similar problem ever arose with mine... so i guess ill pay attention to this thread too... see what i can learn from it

[TrailBlazinMan]

Both the shape of the firing pin retainer and the mainspring affect the speed of the slide traveling rearward due to the slide (through the firing pin retainer) cocking the hammer (against the mainspring.) The faster the slide moves back, the more forceful ejection will be (maybe denting cases) and the shorter dwell time (maybe causing feed issues.)

[Mike_Fontenot]

Both the shape of the firing pin retainer and the mainspring affect the speed of the slide traveling rearward due to the slide (through the firing pin retainer) cocking the hammer (against the mainspring.)

OK, I can see how a stiffer mainspring will slow down the slide movement (in the same way that a stiffer recoil spring does), but it's still not clear to me how the shape of the firing pin stop has any effect ... thanks to you, I now understand that it is the bottom of the fps that contacts the hammer, but how do different SHAPES of that bottom surface change the slide speed? And what are the various choices in those shapes?

[Rinspeed]

Do a search for "small radius firing pin stop"

[Darmok]

How does the firing pin stop affect ejection?

TrailblazinMan summarized this well, but just to elaborate... in a nutshell, it changes the leverage point against which the hammer pivots as the slide is moving rearwards, thus transferring more of the slide's energy into the mainspring. I saw it described somewhere using the analogy of a seesaw, where changing the pivot point by just a small amount greatly changes the force required to push down on one end of the seesaw. The original design of the 1911, as John Moses Browning designed it, did not have the huge radius that today's firing pin stops have on them that make the slide easier to rack, but at the cost of increasing slide velocity. The EGW stop helps tune the gun so it is closer to the original (better) design. Here's a thread that discusses it in excruciating detail, and describes the proper way to radius the EGW FPS:

http://forum.m1911.org/showthread.php?t=13060

And the mainspring (as opposed to the recoil spring) also matters? (I've got a 20 lb Wolfe recoil spring on mine, in place of the original 18 lb spring).

The mainspring supposedly matters a lot more than the recoil spring does (also discussed in the above thread) for controlling slide velocity, in a 1911.

I also haven't experimented with any other brands of 10mm magazine. For one thing, I want to stick with a flat-bottomed magazine, and many of the alternatives seem to have the extra plastic piece on the bottom. How has your experience with the Wilson been? For my backup magazine, I bought another Kimber (through Midway).

I wanted all flat-bottomed magazines too at first, but after I ordered the Wilson Combat 9-round mag, which extends a bit below the mag well, I realized how much better it feels to seat the mag with the added length. It's a much more solid-feeling seating. Anyway, to answer your question, among the three mags that I have tried: the Wilson Combat 9-round, the Tripp 9-round, and the factory Kimber 8-round, the Wilson Combat is the only one that has performed flawlessly in my Kimber (except for a couple of issues that weren't the mag's fault). My Kimber mag feeds rounds at too sharp an angle (which I presume is due to a defect, rather than a design flaw), and the Tripp feeds them at too shallow an angle. The WC is the goldilocks mag (just right).

[Mike_Fontenot]

I spent a good bit of time this afternoon trying to inspect the clearance between the inner-lug of the slide-stop, and either (1) the portion of the follower designed to push the lug upward when the last cartridge has been loaded, OR (2) the upper-most bullet in the magazine. It surprised me to see that for some bullet shapes, the clearance between the bullet and the lug is very small ... not much margin for error. I.e., I can see how a bullet, when moving upward in the magazine to the top level, could possibly contact the slide-lock lug and prematurely push it up. AND, it appeared to me that the portion of the lug that the bullet could contact is the SAME portion that the magazine follower is supposed to contact ... if so, I don't see how there is any portion of the lug that can be filed away that won't also affect the (desired) lock-back after the last round is fired.

Here's a question: Both of my magazines are reasonably tight when the slide is closed, but when the slide is back, both magazines are quite loose ... they audibly rattle. That same looseness would very briefly occur during the normal cycling of the slide after a round is fired. And that looseness might well reduce the clearance between the new top bullet (as it moves up in the mag) and the inner slide-lock lug. Is that looseness normal?

[Darmok]

I spent a good bit of time this afternoon trying to inspect the clearance between the inner-lug of the slide-stop, and either (1) the portion of the follower designed to push the lug upward when the last cartridge has been loaded, OR (2) the upper-most bullet in the magazine. It surprised me to see that for some bullet shapes, the clearance between the bullet and the lug is very small ... not much margin for error. I.e., I can see how a bullet, when moving upward in the magazine to the top level, could possibly contact the slide-lock lug and prematurely push it up. AND, it appeared to me that the portion of the lug that the bullet could contact is the SAME portion that the magazine follower is supposed to contact ... if so, I don't see how there is any portion of the lug that can be filed away that won't also affect the (desired) lock-back after the last round is fired.

That small margin of error definitely depends on the make of the mag too. With my Tripp mag, the nose of the bullet hits that lug on the slide stop every time. With my Wilson Combat mag, it clears it every time. Oh, I think I may have forgotten to mention earlier that when doing that test with the slide removed, you'll want to push the top-most round in the mag forward a bit before (or after) you seat the mag, to simulate the position that the round will likely be in by the time the mag is nearly empty, due to inertial follow.

As for filing away that lug in such a way that it doesn't affect the follower, yeah, that's a real fine line to walk. I think my Tripp follower makes more positive contact with that lug than my Wilson Combat follower does, so the Tripp would probably be more forgiving of removing metal from that lug than the WC would. I still like the WC mag better though in my Kimber. The only thing I don't like about the WC follower though is that it is plastic, so I hope it doesn't eventually wear away to the point that it begins to fail to lock back the slide.

I'll know tomorrow if filing away some of that lug, on the modified slide stop that Kimber sent me, made it more likely for the slide to fail to lock back.

It's rather curious to me that the 1911 was designed with so little tolerance between a properly-functioning slide stop and one that causes malfunctions, though perhaps this is only really a problem with 10mm's--a caliber that the 1911 was never designed for.

Here's a question: Both of my magazines are reasonably tight when the slide is closed, but when the slide is back, both magazines are quite loose ... they audibly rattle. That same looseness would very briefly occur during the normal cycling of the slide after a round is fired. And that looseness might well reduce the clearance between the new top bullet (as it moves up in the mag) and the inner slide-lock lug. Is that looseness normal?

That's an interesting observation. I don't really know what normal is in this instance since I don't have anything to compare my Kimber to, but your idea that the looseness might reduce clearance when the slide is back makes sense to me.

[Mike_Fontenot]

It's rather curious to me that the 1911 was designed with so little tolerance between a properly-functioning slide stop and one that causes malfunctions, though perhaps this is only really a problem with 10mm's--a caliber that the 1911 was never designed for.

It would seem that .45" bullets would reduce the clearance even more, because they are about 0.025" closer to the inner slide-stop lug than the 10mm (.40"). Maybe they are enough shorter than the 10mm cartridges that they usually remain behind the lug?

I don't really know what normal is in this instance since I don't have anything to compare my Kimber to, but your idea that the looseness might reduce clearance when the slide is back makes sense to me.

I think the reason the mag is fairly snug, when the slide is forward, is probably just due to the fact that the follower (or the uppermost bullet) is being forced (by the mag spring) against the bottom of the barrel. But whenever there is no barrel above the mag follower (or topmost bullet), there's nothing constraining the magazine other than the magwell. And there needs to be SOME looseness there, to get the mag to drop freely when the mag release is pressed. But I still don't know if mine are TOO loose or not.

I've also realized that, if the only reason, that my slide was prematurely locked back, was due to the slide-lock being engaged in the slide notch, then the slide would NOT have slammed on my thumb when I pushed the mag down with my other thumb. I understand now that the thing that normally disengages the slide-lock from the slide notch (when you pull back on the locked-back slide, after inserting a new loaded mag), is the forward edge of the slide notch ... THAT is what forces the slide-lock down and out of the notch. So pushing down on the mag wouldn't have disengaged the slide-lock.

I think there may be only two possible causes for the slide slamming forward on my thumb ... either (1) the slide-lock was engaged in the slide notch, and the topmost bullet was above the inner slide-stop lug, and the bullet pushed the slide-lock out of the slide notch when I pushed down on the bullet, or (2) the slide-stop was NOT engaging the slide notch, the slide was being held back by the bullet itself (wedged horizontally between the firewall of the slide and either the front of the mag, or maybe the bottom of the feed ramp), and when I pushed the bullet downward, that removed the obstruction, and the slide slammed forward.

Unfortunately, I don't know which of those two alternatives was the real culprit. I DO remember initially thinking (incorrectly) that the top of the mag might have been bent (a perception that was probably caused by there being an unusual space between the cartridge case and the portion of the mag that keeps the cartridges from moving straight upward out of the mag). I also had the perception that the bullet was not angled upward in the normal way for the topmost bullet (especially when the mag is close to being full). But that could be consistent with either of the above two alternatives, I think.

Maybe the best I can do now is just try to be much more observant if it happens again at my next range session (unfortunately almost a month away). In the meantime, I'll probably try to get some other types of mag to try, but I do need to find flat-bottom ones ... my concealment arrangement for that gun is barely acceptable now, and I don't think I can tolerate any additional grip length. Does Wilson make ANY 10mm mags that are flat-bottomed?

[Darmok]

I think there may be only two possible causes for the slide slamming forward on my thumb ... either (1) the slide-lock was engaged in the slide notch, and the topmost bullet was above the inner slide-stop lug, and the bullet pushed the slide-lock out of the slide notch when I pushed down on the bullet, or (2) the slide-stop was NOT engaging the slide notch, the slide was being held back by the bullet itself (wedged horizontally between the firewall of the slide and either the front of the mag, or maybe the bottom of the feed ramp), and when I pushed the bullet downward, that removed the obstruction, and the slide slammed forward.

I suppose it could easily be either, but my gut feeling is that #1 was the issue. I think the top-most round jumped over the slide stop lug, pushing it up into engagement on the slide notch as it did so (probably just barely). I think that was happening on mine too, until I filed off some of the metal from that lug.

In the meantime, I'll probably try to get some other types of mag to try, but I do need to find flat-bottom ones ... my concealment arrangement for that gun is barely acceptable now, and I don't think I can tolerate any additional grip length. Does Wilson make ANY 10mm mags that are flat-bottomed?

Your reason for preferring a flush-fitting mag is completely understandable. Unfortunately I don't think Wilson Combat makes a flush-fitting 10mm mag. Tripp does though, and now that I think I've gotten my slide stop almost adjusted properly, I really like my Tripp 9-rounder. If I were going to try another mag next, I would order a Chip McCormick mag. They do make a flush-fitting 10mm mag, and it holds 9 rounds to boot. I'm not sure how they managed to squeeze that many 10mm rounds into a flush-fit. In fact, I think I just talked myself into ordering one myself (as if I really need another mag).

One thing I've noticed about the Wilson Combat mag in my Kimber is that it's tough to get seated when the mag is full and the slide is closed, due to the tension against that top round. It takes a small sharp whack to seat it (not a big deal)--just trying to push it into place doesn't work.

I just got back from the range after having filed off some more of that slide stop lug. What a difference that made. I went from having a 6% malfunction rate (all premature slide lockbacks, all with the Tripp mag--the Wilson Combat mag performed flawlessly again), down to a 1% malfunction rate (just a single premature slide lockback, again with the Tripp mag. That's still too high a malfunction rate, but definitely a big step in the right direction. I just finished filing off a tiny bit more, and now I can't make the top round on that Tripp mag to hit that lug anymore, no matter how hard I try, so it seems right now. It seems the difference between a malfunctioning slide stop and a properly-adjusted one is only about 5 thousandths of an inch. That's how much I just now took off, and it wasn't a lot of swipes with my smooth-cut mill file. It's definitely possible to make this adjustment without making the follower prone to missing the lug and failing to lock back the slide, if you make tiny adjustments.

[Mike_Fontenot]

Unfortunately I don't think Wilson Combat makes a flush-fitting 10mm mag.

Yeah, you're right. I called them today, and asked if that plastic piece at the bottom of the mag was removable, leaving the standard flat plate ... they said no, and that they don't make ANY mags that have the flat flush bottom plate.

[...] now that I think I've gotten my slide stop almost adjusted properly, I really like my Tripp 9-rounder. If I were going to try another mag next, I would order a Chip McCormick mag.
[...]
I just got back from the range after having filed off some more of that slide stop lug.

Can you describe which regions you have removed? The follower needs to contact somewhere along the inner edge of that flat bottom surface of the inner lug. But I THINK that same edge of that flat bottom surface is also what the bullet is most likely to contact as the bullet moves upwards. Do those likely points of contact on that edge occur at slightly different points fore and aft along that edge? I.e., if the follower extends farther forward than the bullet does, you could perhaps file back that edge at its aft-most point, and still not affect the contact with the follower. OR, did you just slightly file back that entire edge, and the follower extends close enough to the slide that it still makes contact with that bottom edge of the lug?

And which slide-lock did you modify, the original one, or the replacement one that I think Kimber sent you (same replacement that they sent me, I suspect)? I got a LOT of premature lock-backs with that original, and only one (out of several hundred rounds) with the replacement one. But I'd be more comfortable experimenting on the original one.

Thanks for those tips on the other two types of mag ... maybe I'll get lucky, and the Chip McCormick won't require any filing.

[Darmok]

Can you describe which regions you have removed? The follower needs to contact somewhere along the inner edge of that flat bottom surface of the inner lug. But I THINK that same edge of that flat bottom surface is also what the bullet is most likely to contact as the bullet moves upwards. Do those likely points of contact on that edge occur at slightly different points fore and aft along that edge? I.e., if the follower extends farther forward than the bullet does, you could perhaps file back that edge at its aft-most point, and still not affect the contact with the follower. OR, did you just slightly file back that entire edge, and the follower extends close enough to the slide that it still makes contact with that bottom edge of the lug?

This is hard to describe in words... I'll use fore/aft/left/right/top/bottom directions, as if the slide stop is installed in the gun and the muzzle points fore...

I mostly removed metal from the aft right edge of the lug (and inadvertently the fore right edge too--so basically the whole lower half of the right side of the lug), while trying to remove as little as possible from the width of that flat bottom surface. In other words, I tried to more reshape that surface of the lug, rather than to shorten its width from right-to-left. I did shorten it to some degree though--I think that was necessary.

Specifically, what I did was first install the slide stop in the frame as I described earlier, with the slide left off of the gun. I then loaded two rounds in the Tripp mag, then pushed the top round as far forward as I could get it and still be able to load the mag into the gun (maybe an eighth of an inch or so). I then reached down through the top of the frame and pushed it forward a bit more until it was up against the feed ramp on the barrel. Then I pushed the slide stop against the frame securely, so it was against the frame as far as it could go (to exaggerate the contact with the top round in the mag), while I loaded the mag into the mag well and tried to get the cartridge nose to hit that lug (it helped to push against the bottom of the mag in such a way that the top angled over against the slide stop), while holding the slide stop securely in place so it wouldn't move (or sometimes letting it move, so I could make sure it was hitting). I moved the mag up and down against the lug until it made a distinct brass mark on the lug.

I also tried coloring the bullet nose with a black marker to try to get the black to transfer over to the lug, but that didn't work as well. Maybe white correction fluid would work, if you painted onto the bullet in several coats to make it thick.

Then I removed the slide stop, and filed down just the spot on the lug with the brass mark on it. I kept repeating that until the round seemed to clear the lug acceptably, but just barely. I kept measuring it with some accurate dial calipers to make sure that I wasn't removing more than a few thousandths of an inch. It's probably better to be able to force a round to be able to hit that lug with some effort, than to take off too much metal and have too much of a gap, at least until you can test it.

And which slide-lock did you modify, the original one, or the replacement one that I think Kimber sent you (same replacement that they sent me, I suspect)? I got a LOT of premature lock-backs with that original, and only one (out of several hundred rounds) with the replacement one. But I'd be more comfortable experimenting on the original one.

I started out on the original stop, since I figured it wouldn't matter if I screwed it up. Sure enough though, I did screw it up--I took off way too much metal. It seemed fine on my workbench, but when I took it to the range, it became clear that I overdid it. So then I started modifying the replacement stop, but I was much more careful this time to take off smaller amounts of metal, and test it before taking off more.

[Mike_Fontenot]

Thanks for that description.

BTW, I looked closely at the bullet shapes of each type of cartridge that I shot last weekend. Two of the cartridges were new to me: both Underwood, with two types of bullets: gold dot jhp's, and XTP jhp's. The gold dots had a substantially wider cavity than the XTP's (which had perhaps the smallest cavity of any of the types I used). The second widest were the BuffaloBores. The DoubleTaps had a wider cavity than the XTP's, but the shape was more nearly linear (less convex shape as it narrowed town to the cavity). The BuffaloBores were fairly wide mostly because of their very convex shape ... their cavities are a good bit smaller than the gold dots, but larger than the XTP's..

So the gold dots looked to me like they would have the minimum clearance from the slide-stop lug, out of all the bullets. Unfortunately, I didn't establish WHICH type of cartridge was the one that jammed (IF there was a jam), but I THINK it might have been the gold dot. I guess it's also possible that the cause might have been due to the way the previous bullet fired and ejected, rather than due to the shape of the bullet that jammed.

One complication in trying to infer what caused this failure (which had never happened to me before, out of about 500 rounds or so), is that this is the first time I've shot my gun since Kimber shortened the ejector a bit (in order to cure a newly appeared problem that I couldn't MANUALLY eject a cartridge ... it would extract, but wouldn't make it out of the ejection port. The ejector was also fairly loose (and Kimber fixed that), and that might have been the cause of the ejection problem, rather than the length of the ejector. It's always easiest to infer the cause a new type of failure, if there has only been ONE change since things were working OK, and unfortunately, that's not the case here ... multiple possible changes.

[Darmok]

Yeah, Mike, that's a good point about different 10mm rounds having different bullet nose shapes, potentially making more or less contact with that slide stop lug. I probably should have tried out a few other brands before I started messing around with removing metal from the lug, just to make sure that Prvi Partizan ammo isn't unusually wide. Looking at some photos of other ammo that I am considering trying though (like DoubleTap 200gr WFNGC hardcast, which looks very straight-sided), I suspect that some other brands are considerably wider at the point where they make their closest approach to that lug. I suspect that I am going to end up using certain mags for certain ammo brands, rather than trying to adjust the lug for one-size-fits-all.

[Mike_Fontenot]

I called Kimber this morning, and described the failure I had last weekend, and also described the half-dozen or so copper/brass-colored marks that are on the inside surface of the slide, on the side opposite the ejection port, and just slightly past the far edge of the ejection port (and occupying the middle half of the length of the ejection port).

They said those marks are normal, and that I can safely ignore them.

They also said that both of the possible causes for the failure, that I've settled on, DO sometimes occur. They said that they HAVE heard of cases where a cartridge itself can (in a horizontal position) jam the slide open. And they HAVE heard of cases where the bullet can push the slide-lock lug up, and also cases where the bullet can get on top of the slide-lock lug, and cause the slide to slam shut if you push that cartridge down. But there didn't appear to them to be any single sure-fire fix ... they just advised me to be very observant of any future occurrences.

Their primary piece of advice was to NOT mix different types of cartridge in a single magazine. I hated hearing that, because my philosophy has been that using several different types in each of my magazines would improve reliability and effectiveness under a variety of conditions ... I haven't wanted to "put all my eggs in one basket" ... I'd LIKE to have different penetration and expansion characteristics, etc, in a single magazine.

Besides my not being observant enough, right after the failure, I ALSO wish I had tried to pull the slide all the way to the stop, and see if THAT would free up the mag to drop. Or, I MIGHT have been able to release the slide from that rear-most position, and gotten the top round to chamber ... either way, it might have allowed me to get the gun back into action pretty quickly.

[Darmok]

Their primary piece of advice was to NOT mix different types of cartridge in a single magazine. I hated hearing that, because my philosophy has been that using several different types in each of my magazines would improve reliability and effectiveness under a variety of conditions ... I haven't wanted to "put all my eggs in one basket" ... I'd LIKE to have different penetration and expansion characteristics, etc, in a single magazine.

Yeah that's not something I like to hear either. My Kimber is (in part) a woods carry gun, and I never know if the biggest threat I'd encounter there would be a large animal (where a heavy hardcast round would arguably be best) or a 2-legged threat (where a hollow point would be preferable). So my thinking had been to alternate the two in a mag, but I've heard enough people say not to do that that I am having second thoughts about that practice.

[Darmok]

I just thought I would post back here with my observations after receiving the Chip McCormick 9-round 10mm 1911 magazine that I ordered. It sure arrived quickly--3 days after I placed the order. Here's how it compares with the Tripp and Wilson Combat 9-round 10mm mags:

Chip McCormick Super Mag:
- All steel, including follower, except for optional plastic base pad
- Flush-fitting to bottom of mag well
- Optional base pad screws onto base plate with 2 screws. This pad is huge--probably great for competition, but I definitely wouldn't use it for carry.
- Base plate appears to be non-removable (a negative point for me, since it doesn't seem to allow any means of replacing the spring or cleaning the inside of the mag).
- Follower ledge provides very good contact against the slide stop lug
- Less clearance between the nose & case of the round, and the slide stop lug, than the Wilson Combat mag, but very similar to Tripp mag.
- Nose of cartridge points higher toward the chamber than either the Tripp or Wilson Combat mags, which feed the round at a shallower angle

Tripp 9R-10MM-RG:
- All steel, including follower. Base pad is either polymer, or for an extra charge, alloy
- Extends beyond bottom of mag well
- Base pad is removable, so mag can be disassembled
- Follower ledge provides very good contact against the slide stop lug
- Less clearance between the nose & case of the round, and the slide stop lug, than the Wilson Combat mag, but very similar to McCormick mag. Caused too many premature slide lockbacks on my Kimber, until I filed down the slide stop lug.

Wilson Combat 47NX:
- Steel body, nylon self-lubricating follower, plastic base pad
- Extends beyond bottom of mag well
- Base pad is removable, so mag can be disassembled
- Follower ledge provides less contact with the slide stop lug than either of the other mags
- The most clearance between the cartridge and the slide stop lug of the three mags

So what this all means in my Kimber 10mm...

The Wilson Combat mag seems more likely than the other two to cause the slide to fail to lock back after the last round is fired, if the slide stop lug is not long enough. With the other two mags, I was able to pull the slide stop away from the frame a bit, to a position that it would not normally be in, and still cause the slide stop to move up to lock position, when testing the gun with the slide removed. With the stop in this position, I was able to get the Wilson Combat follower to fail to move the slide stop. I don't mean this as a criticism, as the Wilson Combat mag should properly actuate the slide stop as long as the slide stop is the proper length, but you would have to be more careful how much you shorten the slide stop lug if you started removing any metal from it, than with either of the other two mags.

The Wilson Combat mag, conversely, seems the least likely of the three to prematurely cause the slide to lock back, as caused by the nose of the bullet of the last round or two in the mag hitting the slide stop lug. There seems to be plenty of clearance between the round and the slide stop lug, when the round is sitting a bit forward due to inertial follow.

I'll reserve comment on whether the high cartridge nose angle on the McCormick mag is good or bad, until I've had a chance to shoot with it. The high nose angle on my factory Kimber mag did cause some jams, but I think I probably had an out-of-spec factory mag. I did have some feeding problems with my Tripp mag that I think were due to the shallow feed angle, but they seem to have cleared up as everything broke in. It does seem that the follower can be easily bent on both the Tripp and the McCormick mags to change the feed angle, though I have no idea if this would adversely affect the function of the mag otherwise. The nylon Wilson Combat follower can't be adjusted, except by bending the feed lips on the mag body.

The instructions insert that came with the McCormick mag stated that the lug on the slide stop (he calls it the slide stop "lobe") should be at least 0.195". Assuming I measured mine at the correct points, my latest modification to my slide stop made it just a hair shorter than that, so I hope I didn't overdo it.

Assuming the McCormick mag functions flawlessly, I think that's going to be my main carry mag. Flush-fitting, 9-round capacity, and all-steel construction, are important points for me.

Your mileage may vary, if using any of these mags in a .45 1911 or in a non-Kimber 10mm, or in a Kimber with the slide stop properly adjusted.

[Mike_Fontenot]

Thanks for all that good info ... very helpful. Couple of questions:

[...] Chip McCormick Super Mag: [...]

I've put a Chip McCormick 10mm "Shooting Star" mag on my wishlist at Midway ... it's out-of-stock, but expected back in about a week or so. Is that the same as the "Super Mag" you ordered? (I looked at the Chip McCormick website, and there only appears to be one 10mm mag.)

Where did you buy yours?

I also wishlisted a Wilson ... also out-of-stock until close to the end of this month. Can you measure the basepad on your Wilson, and tell me by how much that extends the length of the grip? I doubt that I can afford ANY increase in length, but I may have to re-think that, if I can't get any other mag to work reliably.

I've got my Eclipse all reloaded now, and back under my arm every day, under my shirt, in its vertical shoulder holster. When it's in that "mode", I don't mess with it! So I probably won't get any more new observations or revelations until I shoot it on June 2 or 3. Hopefully I'll have the Chip McCormick mag by then, and can include it in the tests.

I'll be very interested in hearing how that higher feed angle of the Chip McCormick works out for you on your next range trip (probably sooner than mine, I suspect). All of its other characteristics sound ideal, to me.

[Darmok]

I've put a Chip McCormick 10mm "Shooting Star" mag on my wishlist at Midway ... it's out-of-stock, but expected back in about a week or so. Is that the same as the "Super Mag" you ordered? (I looked at the Chip McCormick website, and there only appears to be one 10mm mag.)

Where did you buy yours?

I bought mine directly from McCormick's website (just Google "CMC Mags"). With shipping times as fast as I experienced, I don't see any reason to buy them elsewhere, unless you find a really good price. He earned big points with me for that turnaround time.

According to his website, the Shooting Star is only available in .45ACP. The Super Mag comes in .38 Super or 10mm. It's possible that some 3rd-party vendors might have a 10mm mislabeled as a Shooting Star.

I also wishlisted a Wilson ... also out-of-stock until close to the end of this month. Can you measure the basepad on your Wilson, and tell me by how much that extends the length of the grip? I doubt that I can afford ANY increase in length, but I may have to re-think that, if I can't get any other mag to work reliably.

Using my metric calipers, it measures 9.5mm (about a centimeter) below the bottom edge of the factory Kimber mainspring housing. I was pretty resistant to a non-flush-fitting mag too before I ordered this Wilson Combat mag, but I ordered it anyway strictly for range use. I must say that it looks very nice on my Kimber Eclipse Custom II. The black base pad looks perfect on the gun. I ordered the optional alloy base pad on the Tripp mag, and that one looks out of place on this gun, but at least it helps easily differentiate it from the others. I suppose it would depend on which grips you have though. Looks are important on this beautiful gun--everything has to work together aesthetically, as I'm sure you'd agree.

I've got my Eclipse all reloaded now, and back under my arm every day, under my shirt, in its vertical shoulder holster. When it's in that "mode", I don't mess with it! So I probably won't get any more new observations or revelations until I shoot it on June 2 or 3. Hopefully I'll have the Chip McCormick mag by then, and can include it in the tests.

Very cool, I should try that carry mode one of these days. So far I haven't carried mine anywhere except at the range, as I usually carry a 9mm.

So tell me, did you end up with an "idiot scratch" under your slide stop on the outside of the frame, like I did?

I'll be very interested in hearing how that higher feed angle of the Chip McCormick works out for you on your next range trip (probably sooner than mine, I suspect). All of its other characteristics sound ideal, to me.

If my week goes well, I should be testing it out on Tuesday. If I forget to post back here, feel free to remind me and I'll give you a report.

[Mike_Fontenot]

According to his website, the Shooting Star is only available in .45ACP. The Super Mag comes in .38 Super or 10mm. It's possible that some 3rd-party vendors might have a 10mm mislabeled as a Shooting Star.

http://www.cmcmags.com/othermags.html

The webpage I went to (see above link) showed the "Shooting Star" wording to the right of the .38Super mag, and I THINK they intended that that also applies to the 10mm. They put the .38Super and the 10mm mags on their own separate page. When you click on the "Shooting Star" page (instead of the "10mm and .38" page) , it only lists .45ACP, but I think that's just a quirk of the way they've designed their webpage. Did your shipping receipt have either the "Shooting Star" or "Super Mag" wording?
__________

9.5 mm is about 3/8" ... definitely not negligible for me ... hope the Chip McCormick works.
_____________

"Idiot Scratch": Yeah, I did that too. Kimber polished it out (without me asking) on its first trip back to Kimber (the loose plunger tube problem). I actually didn't worry about the scratch very much (although I DID figure out how to avoid adding to the scratch, on subsequent re-assemblies) ... hopefully my Eclipse 10mm is going to be my EDC, and I can't worry to much about cosmetics for a "working gun" (although I DO appreciate its good looks, even though that didn't enter into my purchase decision).

[Darmok]

http://www.cmcmags.com/othermags.html

The webpage I went to (see above link) showed the "Shooting Star" wording to the right of the .38Super mag, and I THINK they intended that that also applies to the 10mm. They put the .38Super and the 10mm mags on their own separate page. When you click on the "Shooting Star" page (instead of the "10mm and .38" page) , it only lists .45ACP, but I think that's just a quirk of the way they've designed their webpage. Did your shipping receipt have either the "Shooting Star" or "Super Mag" wording?
__________

9.5 mm is about 3/8" ... definitely not negligible for me ... hope the Chip McCormick works.
_____________

"Idiot Scratch": Yeah, I did that too. Kimber polished it out (without me asking) on its first trip back to Kimber (the loose plunger tube problem). I actually didn't worry about the scratch very much (although I DID figure out how to avoid adding to the scratch, on subsequent re-assemblies) ... hopefully my Eclipse 10mm is going to be my EDC, and I can't worry to much about cosmetics for a "working gun" (although I DO appreciate its good looks, even though that didn't enter into my purchase decision).

My receipt just says "10mm 9rd Stainless Mag w/Pad." There was a catalog included with my order, and from what I can tell, it appears to me that the Shooting Star only pertains to .45ACP. The 10mm mags are in the next section down in the catalog, in their own separate section. I don't know though, it might be worth sending McCormick an e-mail to be sure.

As for the idiot scratch... that's interesting, I had no idea that could be polished out. From what I had been reading, any attempts to do so would simply remove the dark upper coating (which is apparently just a blued finish over stainless steel, that has been mostly removed) and reveal the bright stainless steel beneath it. Does the finish look at all lighter around that spot now?

[Mike_Fontenot]

As for the idiot scratch... that's interesting, I had no idea that could be polished out. From what I had been reading, any attempts to do so would simply remove the dark upper coating [...]

The "idiot scratch" I'm talking about was on the shiny flat left side of the frame, starting from the slide-stop outer lug, and arcing downward for about a half-inch (caused by me inserting the slide-stop pin, with the slide-stop lug initially angled downward and contacting the side of the frame, then being rotated upward so that it latches with the plunger pin ... wrong way to do it ... you need to lower the slide-lock lug right onto the plunger pin, from above (or only VERY slightly below) as you are inserting the slide-lock pin through the barrel link). So the black coating (on top of the slide, and on the front portion of the frame) wasn't involved at all.

[Darmok]

The "idiot scratch" I'm talking about was on the shiny flat left side of the frame, starting from the slide-stop outer lug, and arcing downward for about a half-inch (caused by me inserting the slide-stop pin, with the slide-stop lug initially angled downward and contacting the side of the frame, then being rotated upward so that it latches with the plunger pin ... wrong way to do it ... you need to lower the slide-lock lug right onto the plunger pin, from above (or only VERY slightly below) as you are inserting the slide-lock pin through the barrel link). So the black coating (on top of the slide, and on the front portion of the frame) wasn't involved at all.

That's not the black coating that I was talking about. That's where my idiot scratch is too, and exactly how mine happened, before I figured out the proper way to insert that stop (the way you do it). Incidentally, I've found that the replacement slide stop that Kimber sent me is much harder to insert than the original stop.

What I meant is that apparently the way Kimber creates that slightly darkened appearance on the non-painted areas of the slide is by bluing the entire frame, on top of the stainless steel, and then removing all but a trace of the bluing from the stainless steel areas. The idiot scratch (on mine, anyway) isn't so much a scratch, as it is a removal of more of that bluing on that spot, thus exposing shiny stainless steel beneath.

I've read about people polishing out that idiot scratch with a green Scotchbrite pad, or steel wool, but it just makes the finish much brighter around the polished area. In other words, they're not polishing off the scratch, but polishing off the remnant bluing to match the color of the scratch. So if Kimber was able to remove your scratch without a trace, Mike, I am wondering if they might have actually polished your entire frame, to blend it in, or if they perhaps added more bluing to that spot. Can you tell if the spot that was fixed is the same color as the other side of the frame?

I've been considering polishing mine out by lightening the entire frame with a Scotchbrite pad, which would create a tri-tone effect: bright stainless frame, darker stainless slide, and black painted areas. It might look kinda cool, but I am hesitant to do so without knowing how it will turn out.

[Mike_Fontenot]

So if Kimber was able to remove your scratch without a trace, Mike, I am wondering if they might have actually polished your entire frame, to blend it in, or if they perhaps added more bluing to that spot. Can you tell if the spot that was fixed is the same color as the other side of the frame?

I can't see any difference between the area they polished to remove the scratch, and any other region of the (non-black) frame or slide ... and both sides of the frame look the same to me. (And when Kimber returned my gun from that trip, they didn't describe any extensive refinishing of the whole frame ... I definitely got the impression that they had only polished the small area around the scratch).

But I also am not seeing the very slight blueing residue that you describe ... it's just always looked like bright stainless steel to me (as opposed to the flatter (but still un-colored) finish that a lot of stainless pistols have). The Kimber webpage describes the Eclipses as having a "brushed stainless" finish on the "flats" of the frame and slide ... I don't know exactly what that means, but I've never interpreted it to imply any slight blueing residue. (I guess "brushed stainless" means that you don't see your reflection in it, like for some mirror-like stainless finishes ... but it's not "flat" either, like for some other stainless finishes ... it's somewhere in-between). I wonder if the finishes on our two Eclipses are perhaps different?

(I agree that the replacement slide-stop is harder to re-insert than the original ... I suspect that it may be slightly longer, requiring the plunger pin to be pushed farther into the plunger tube, with more compression of the plunger spring (which might make that slide-stop more resistant to being prematurely pushed up). It's worth the extra hassle during the re-insertion, I think.)

On a previous subject, I was very glad to hear that you had concluded that the clearance between bullet and slide-stop lobe is greater for the Chip McCormick mag than the other mags, because that seems likely to be very pertinent to my malfunction. But I've wondered if that conclusion is influenced by the greater feed-angle of that mag. I.e., is the increased clearance due (or partly due) to the fact that the bullet that is about to be fed is higher above the lobe than in other mags, and not just due to the bullet being a greater HORIZONTAL distance from the lobe?

The reason I'm concerned about that, is that I THINK the problem of the lobe being pushed up by a bullet (so that the slide prematurely gets locked back) CAN sometimes be caused before the bullet (that's doing the pushing) emerges to its highest level before being fed ... i.e., I think the bullet may push the lobe upward when it is still parallel with all of the lower bullets in the mag, not after its tip has risen so that it is sloping more than the bullets below. I think the bullet doing the pushing MAY even sometimes be the next bullet below the top bullet in the mag. So, bottom line is that I'm hoping that you observed the HORIZONTAL clearance between bullet and lobe to be greater for the Chip McCormick mag than for the other mags. What do you think?

[Darmok]

Regarding the residual bluing on the finish, here is where I got that info. Scroll down to the "Eclipse Video Transcript" section, if you don't feel like watching the video:

http://www.gunshopfinder.com/Kimber/eclipsetarget2.asp

I had also read a forum post or two by people who own the Kimber Eclipse Custom II who noted that it made the slide finish lighter when they tried to polish out idiot marks. So I'm really curious how Kimber fixes those blemishes. Perhaps I'll call them and ask.

As for the clearance on the various magazines... I see what you are getting at that perhaps the clearance I am seeing is due to the higher nose angle of the top round on the mag, and that's a good point. I just now took a closer look at it though, this time using a stronger flashlight, and the clearance is definitely horizontal clearance. I don't think it would have made any significant difference if the nose angle was shallower. I do, however, need to revise what I said before, after using the brighter light:

The Tripp and the McCormick mag actually seem to have very nearly the same horizontal clearance between a forward-sitting cartridge and the slide stop lobe. I may have thought otherwise earlier because I didn't have the round sitting in quite the same position earlier (it's possible to wiggle the round side-to-side just a bit in the mag). On both of those mags, the top-most round, when it is pushed forward as far as it will go so it is just about hitting the entrance to the chamber, the front edge of the case (the mouth end of the case) is actually touching the lobe. It's not touching it hard enough to move the slide stop, at least how I have the lobe filed down, but it's definitely touching, and I am wondering now if it wasn't the bullet nose that was causing my premature slide lockbacks earlier, but rather the case. It's a moot point though, as either way the slide stop lobe needed to be adjusted the same way.

The Wilson Combat mag has a very noticeable gap between either the bullet or the case, and the slide stop lobe. So now I think the WC mag is the least likely to cause premature slide lockbacks. That makes sense, as I have never experienced a premature lockback with that WC mag, though I've experienced many with the Tripp mag, at least before I adjusted the slide stop.

I still think the shelf on the follower on the Wilson Combat mag is more likely to miss (or jump over) the slide stop lobe though, if that lobe is the wrong length, than either of the other two mags, potentially causing the slide to fail to lock back. That makes sense too, since the WC mag is the one that was causing the slide to fail to lock back the most often when I was using that original slide stop that I had filed down too much. Again, I mean this as no criticism of the Wilson Combat mag, which is very well-made, and many people swear by them. The same goes for the Tripp mag. I'm sure they both function perfectly in a gun with the proper slide stop length.

So I'm not really sure which mag is the least prone to causing malfunctions overall, as it really depends strongly on that lobe length.