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Old August 1, 2014, 09:48 PM   #1
PakWaan
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Live round ejected with previous spent casing - ideas?

My new Sig P938 is ejected live rounds. The gun is new, bought it last month, it has a total of 700 rounds through it. Today I ran 100 rounds through the gun, using 2 different magazines, each loaded with 6 rounds every time. On 5 occasions, after shooting 5 rounds, the slide locked to the rear and the gun was empty. I found a live round on the ground each time.

During one of the cycles, a live round is being ejected with the spent casing. But since it goes bang again with each trigger pull, I'm guessing it must be the last round in the magazine that gets ejected, because I can't imagine it happens in the middle of a magazine and still loads the next round in addition to the one that got ejected.

It stumped the gunsmith at my LGS today, where I was shooting it.

I was thinking magazine lips or springs, but it happens with 2 magazines and they are both new. I borrowed a new 3rd magazine from the gun store, and twice, on the last round of the magazine, this is what I got:



I just got it back from Sig yesterday, because it wouldn't feed hollow points. They polished the feed ramp and now it feeds HPs with no problem. Sounds like it needs to go back to the factory again.....
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Old August 1, 2014, 10:20 PM   #2
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The only way I can come up with for that picture to happen is if the magazine is releasing the round early. That would also be consistent with live rounds ejecting.

That means that:

1. The feedlips are too widely spaced apart.
OR
2. The feedlips are too flexible and/or the magazine spring is way too strong and is forcing the follower up with enough force to spread the lips apart.

The fact that it's happening with more than one magazine is strange.

The feedlip spacing on the magazine should be something like 8.4mm to 8.6mm. I'd measure the spacing with magazine unloaded (follower all the way up) and then again with the magazine disassembled so the follower is totally out of the picture.
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Old August 2, 2014, 08:48 AM   #3
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Weak mag springs and/or spread feed lips. As already commented, the mag is releasing the last round too early. Since it's always the last round, that suggests it's probably weak springs rather than spread feed lips.



[Must resist temptation to point out that the OP should have bought a Colt.]
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Old August 2, 2014, 09:12 AM   #4
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Sometimes, it can be a combination of things, all contributing to the problem.
In addition to the mag springs, a low tension extractor and short overall length cartridges could be culprits.
Maybe.
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Old August 2, 2014, 09:42 AM   #5
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If it didn't do this before Sig polished the ramp, and now it does, then obviously I'd suspect that. The round in the picture got hung up on something that it would not have hung on before the servicing, and didn't feed. Why it's the last round, I don't know, but that's when the mag spring is at it's weakest. If you load one round in the magazine and cycle the slide, does it hang up?
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Old August 2, 2014, 10:35 AM   #6
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Are you sure it's the last round? I'm thinking it might be the first cycled round where the mag spring tension is highest. So if the mags lips are out of spec, it would easily spit two rounds out at the same time.

You should go shoot it again and look for the round where the problem occurs.
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Old August 2, 2014, 01:07 PM   #7
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Use a permanent magic marker to NUMBER the side of the cases before you load them in your mag. You'll know pretty quickly which live round is being ejected...
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Old August 2, 2014, 09:46 PM   #8
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Edited.

That is a light pistol with a relatively heavy load. I think what is happening is that as the magazine empties and there is less tension on the magazine spring, recoil is causing the gun to come back while the top round in the magazine tries to stay where it is. That results in the round jumping out of the magazine without the slide pushing it out. With the round gone, the slide catch can lock the slide back. But the round is not fed since the slide is locked back, so it is free to fall on the ground. If the slide doesn't lock back, the round can jam between the barrel and slide.

Jim

Last edited by James K; August 2, 2014 at 09:56 PM.
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Old August 2, 2014, 10:08 PM   #9
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I'd talk to someone where you had it repaired before and tell them they created another problem. Send it back and tell them you would like a replacement. If it is a few hundred or a few thousand dollars on a gun it is still your money and you should expect a quality piece.
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Old August 3, 2014, 09:44 AM   #10
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Let some one else shoot it to make sure your not limp wristing the gun.
I find it odd that both mags are repeating the same failure.
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Old August 3, 2014, 08:57 PM   #11
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Another test that might yield useful information, put in a loaded mag and cycle the slide by hand.
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Old August 3, 2014, 10:24 PM   #12
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Interesting twist. When this happened a few days ago, I was firing a combination of Gold Dots and Golden Saber - both hollow points, since I had just gotten the gun back from Sig because it wouldn't feed HP ammo. Yesterday, I put 200 rounds of 115 and 124gr FMJ through the gun without it ever happening once. Today, I put 50 trouble free rounds of FMJ through it again, then switched to HPs. Out of 5 magazines of HPs, it happened 3 times, always with the last round. I switched back to FMJ and the problem went away. So it is an issue with HPs only.
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Old August 4, 2014, 02:44 AM   #13
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It it possible that this is a weak magazine spring and the HP is hanging in the feeding while the slide pushes the back of the case up and out?

I would try cycling many last rounds by hand as was mentioned.
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Old August 4, 2014, 08:32 PM   #14
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Sounds like you have feed ramp issues, before and after their fix. I would still send it back.
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Old August 4, 2014, 08:57 PM   #15
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In 1911s this issue would likely be caused by (in decreasing likelihood) a weak magazine spring, overly strong recoil spring, or ramp issue. It might also happen if the mag's feed lips are spread too far. So, I would try a different magazine first and then ship it back to Sig. Even though you have the same problem with two magazines, whose to say there wasn't a bad batch of magazines.
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Old August 4, 2014, 09:28 PM   #16
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I talked to Sig today, they want the gun back again, so I'm shipping it off tomorrow along with the magazines. We'll see what they come up with.
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Old October 4, 2014, 06:54 AM   #17
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** Follow up: After 2 more trips to Sig, the issue appears to be fixed. The 2nd time I sent it back, they said they couldn't duplicate the issue and returned it having done nothing. I took it to the range and it did it again. I had the gunsmith at the range fire it, and it did it to him too. So I called Sig and told them I was going to continue sending it back until they fixed it. On the 3rd trip, they replaced the magazine catch spring. Since getting it back this time, I've only had time to get to the range once, but put 15 mags of hollow points through it with no problems. Hopfully I'll have time next week to put another couple boxes through it and pronounce it cured.
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Old October 25, 2017, 01:05 PM   #18
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I know this is an old thread..but..I just bought a new 1911 C3 and took it to the range for its first time and its doing this same weirdness. everything seemed perfect except it seemed like there were fewer rounds in the mag than i thought a couple times. as i was cleaning up i find 2 live rounds on the counter and floor! the only thing that i was surprised about was how strong the mag springs are! i really had to work at getting the last round in the mag. anyway...just so that you know this is still a happening thing!
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Old November 22, 2017, 02:46 PM   #19
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Invited into this one from afar...so...ok.

In 1910, John Browning put a little bitty bump on top of his 1911 magazine follower.

And now you know why.

Cheers!
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Old November 22, 2017, 05:03 PM   #20
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I agree. My Bersa Thunder did this a few times. It also frequently jammed the last round nose up. After closing the mag lips slightly, problem solved.
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Old November 23, 2017, 01:39 PM   #21
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A classic inertia feed. Most common on the last round in the mag when the mag spring force is the lowest. Check for weak mag springs or the presence of any lube on the feed lips or follower.
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Old November 23, 2017, 03:57 PM   #22
Ride Madone
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Quote:
Originally Posted by Ozzieman View Post
Let some one else shoot it to make sure your not limp wristing the gun.

I find it odd that both mags are repeating the same failure.


Still should not do this even if limp writing the gun. If limp writing is causing this it needs to go in for repair.


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Old November 24, 2017, 05:08 PM   #23
rtv5
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ok so..given there is no lube on the mag follower..what should i do? the mags that came with the pistols are highly polished (SS i guess) could it be just too smooth?
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Old November 24, 2017, 05:14 PM   #24
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Quote:
Originally Posted by 1911Tuner View Post
Invited into this one from afar...so...ok.

In 1910, John Browning put a little bitty bump on top of his 1911 magazine follower.

And now you know why.

Cheers!
Inertia feed from a 1911 type design. If it stumped your local gunsmith you need a new gunsmith.
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Old November 24, 2017, 05:18 PM   #25
rtv5
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well...not sure i should need to consult a local gunsmith on a brand new pistol! maybe SIG might/should care!?!
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