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I received my new Tripp Cobra magazine for my STI 1911 a few days ago, and finally today had a chance to check out this combination of mag/gun/ammo.

And I think I'm about ready to declare it a success.

I ran about 85 rounds (all I had on hand) of my "problem" ammo (Federal Guard Dog) through the new Tripp magazine without a single failure. Based on my prior experiences with this ammo in my other magazines, I normally would have seen at least three instances of the malfunction I was having with this amount of rounds fired (generally occurred about once out of every 20-25 rounds).

Once I stock up on this particular ammo again, I'll run at least another 100 rounds of it with the Tripp mag and look for no failures before I more confidently call my problem resolved. But it certainly is looking much better now.

Thanks to all who recommended I try the Tripp magazine. While my STI and Wilson Combat magazines seem to work just fine with regular 230 grain ball ammo, the Tripp magazine (so far) seems to have done the trick for me for being able to run this particular short, flat nose ammo that I prefer to use as my SD rounds.

Life is good!

AndyC wrote:Just don't oil it.

The Annoyed Man wrote:Cobra Mags from Tripp Research will solve all of your magazine problems. Pricey, but by far the best most reliable 1911 mags I've ever owned.

https://www.trippresearch.com/store/store_1911.html

I just had a conversation with Aaron Tripp at Tripp Research about my issue with the last HP round sometimes "escaping" my current STI & Wilson Combat magazines. After talking with Aaron, I ended up ordering one of their magazines to see if it helps resolve this problem. If it doesn't, I guess my little beauty will be making a trip back to Georgetown.

I'll post an update after I've received & checked out my new Tripp mag.

AndyC wrote:Yes, you are.

Your extractor doesn't just extract fired cases from the chamber - it also holds the cartridge in position on the way into the chamber.

It sounds to me exactly like your extractor is losing control of the rims of the cartridge once it's fed from the magazine up into position (nothing to do with extraction) into place under the hook of the extractor.

The previous rounds don't have this issue because they are being held up in place by the round underneath it in the mag (eg. round 5 is supported up in place under the extractor by round 6 in the mag, etc), which disguises the issue - but when the last round in the mag is slid upward under the extractor (by magazine-spring pressure onto the follower), there are no rounds left underneath to (artificially) support it up in position - so it drops out of the extractor before the slide closes.

I'm guessing that your FMJ cartridges have a slightly thicker rim so the extractor *just* manages to hang onto them during feeding into the chamber - but that the HP ammo has slightly thinner rims and falls out from the extractor.

It's easy to test - strip the pistol and remove the barrel/spring from the slide. Slip an FMJ cartridge under the extractor and shake lightly - it should stay in place. Now try the same thing with one of your HP cartridges - it'll likely fall off.

Here's a rough example of what I'm talking about:


Now, if my first theory is wrong, then great - at least you've checked the extractor and now you can look to the magazine. Either your feed-lips are oily (which allows the last round to shoot forward free of the mag-lips under recoil - or the magazine's spring pressure is so weak on the last round that it allows the same thing to happen. Dry the feed-lips and/or replace the magazine-spring with a stronger one - but because it only happens with one type of ammo and not the other, I'm guessing extractor-tension is too weak.

Well, see, I learned something today. I knew the extractor hooked into the round as it got picked up. But I thought it was just so it would be ready and in position after the round was fired and ready to be pulled out. I did not know that it actually helped to guide it into the bore. Learn something new every day.

And I knew about the "shake" test for checking the extractor tension, but had never done it on this gun. So I did do that last night. I tried several different bullets, different manufacturers, different bullet weights and shapes, including my "problem" ammo. They all held in just fine, including the ammo that is giving me the problem. So I think the extractor is working ok.

I have tried several different magazines from two different manufacturers, and I've observed the problem to some degree on all the ones I've tried. I had not thought about oil on the magazine lips. I do try to keep a (very light) film of oil on everything. So I'll strip that off and see if it improves the situation.

Thanks to everyone for all the suggestions. I will work through all of them as I get a chance. I may still end up having to send the whole thing back to Georgetown, but I'm just trying to see if I can determine the problem first, so maybe I don't have to ship it off for a month or two. I do have other guns I could carry during that time, but my little 1911 is by far my favorite!

Pawpaw wrote:Is that 1911 by any chance a Kimber? If so, call Kimber customer support and tell them about it. They will send you a slide stop that will cure the problem.

I'll second TAM's recommendation of Tripp Research mags. It was on his recommendation that I started buying them.

Pawpaw, no, actually it's an STI. I did contact them, and they sent me another slide lock right away. But that one had an entirely different problem (end of the slide lock had been ground down so much that it would not make contact with the plunger ball at all, so it just flopped up and down totally loose). So I'm a little put out with STI right now. I probably will end up sending the whole thing back to them, and I have confidence that they can get it right once they have it in their hands, but I hate to send it off for a month or two, so I thought I would take a look at it myself first (for what that's worth).

I am going to take TAM's advice and contact Tripp. I knew that he was the guy who actually started STI and sold out, but did not know he was still in business with a different company name. I see he has some different type followers on some of his magazines, so that is definitely on my list to check out further.

G.A. Heath wrote:The Tripp mags are pretty good, I would also go to the 1911 forums and search for "Tuner Approved Mags" and posts by the user "1911 Tuner" or "1911Tuner" I don't remember which way he uses. He is probably the best resource for 1911 information since JMB himself.

Thanks G.A., I'll look into that also.

AndyC wrote:

thatguyoverthere wrote:But, first, here's my problem: using hollow points, sometimes the slide locks back on the last round in the magazine. What I mean is that the slide locks open (because the magazine is empty), but the last round from the magazine is just sitting on top of the empty mag. The round does not get chambered, it's just sitting loose on top of the mag.

You don't have a magazine problem, you have an extractor problem - at least as far as the diameter/thickness of the rim is concerned for your HP ammo (your FMJ ammo likely has a wider/thicker rim, just enough that the extractor *can* hold onto it).

The phenomenon appears to happen only to the last round in the mag because there's nothing left under it to hold its rim up in place under the extractor - unlike all the other rounds before it which have the upward support of the rounds in the magazine below it.

Not sure I follow you Andy. I think the extractor is working ok. It pulls all the empty cases out of the bore and they all get ejected ok. But the last unfired bullet pops out of the magazine prematurely in the last cycle, causing the slide to lock back (since the magazine is empty now) with the unfired bullet just sitting loose on top of the magazine. At that time, there is no empty case left it the bore; it got extracted and ejected when the slide came back. But somehow the last bullet is out of the magazine and just sitting there on top of the magazine, free as a bird. (I feel like Houdini has been messing with my gun! ) Am I totally missing what you're saying?

Thanks. I'll take a look at that.

Has anyone here ever modified a magazine for your 1911? Or built a custom magazine for yourself? Or know of a company that builds custom magazines for 1911s?

Here's my deal. I have a 1911 that is my EDC. I love it, don't want to carry anything else. BUT, it will not shoot hollow point ammo reliably. It WILL shoot regular old ball ammo all day long and never miss a beat. But it chokes on hollow point ammo. Granted, it's a fairly minor type problem, and the problem does not occur every time, but I would prefer to have NO problems with my EDC!

I've tried several different brands of ammo, and also several different magazines from different manufacturers. Results are all the same - unreliable operation with the hollow point ammo. This being my EDC gun, I'd like to run hollow points in it, but have just about decided to simply run plain old GI ball ammo all the time and call it good, since I've never had any problems with that.

But, first, here's my problem: using hollow points, sometimes the slide locks back on the last round in the magazine. What I mean is that the slide locks open (because the magazine is empty), but the last round from the magazine is just sitting on top of the empty mag. The round does not get chambered, it's just sitting loose on top of the mag.

In a lot of cases, conventional wisdom says as the round is coming up the mag, the edge of the bullet is hitting the inside lip of the slide lock (where the follower on the magazine would normally catch it), causing the slide to lock back with a round still in the mag. But in my case, I don't think that totally explains how the bullet ends up outside the magazine, sitting on top of the (now empty) magazine.

What I THINK is happening (at least partially) is that since the hollow point bullets are so much shorter in length than a regular ball round, that the hollow point ammo is working forward in the magazine, with the bullet coming in contact with the inside front of the mag. With the longer ball ammo, that's not an issue. But with the short hollow point rounds, with the bullet being considerably shorter, the bullet just becomes oriented so far forward in the magazine that the lips on the top of the mag don't hold it in the mag when the slide moves back.

I'll admit that I'm new to the 1911 world, so could be missing something. And I still don't have all my questions answered in regard to this problem. But, I'm thinking that if I could add a strip, or a shim, to the length of the inside front part of the magazine, with that added shim being thick enough to hold the bullets to the rear of the magazine, I think that this problem would be fixed. Keeping the bullet to the rear of the mag would keep it away from the inner edge of the slide lock, preventing premature slide lock. The bullet being held to the rear of the mag would also prevent the bullet from popping out of the mag prematurely due to being too far forward for the magazine lips to hold it. The magazine mod would also require notching the carrier, and would require a custom made magazine spring, but I think those would be do-able. If it worked out, I would dedicate a few mags for holding hollow point ammo only, and use other (normal) mags for holding ball ammo for range use.

Sorry for the looooong post, but what do y'all think?