FTE Issues On The M18

Unless you determine the real cause, there's no guaranty that the parts ordered will fix it.

First, is it a new gun? Are you using the original mags? Does it do this with both mags?

What brand and bullet weight ammo are you using? Is it factory ammo or reloads?

Slide not locking back is a common grip related issue. During recoil, your thumb (or other part of your hand) can make contact with the slide stop preventing it from engaging. Try shooting a few mags one handed.

I wouldn't change a single part unil you actually know whats causing it. More than likely its ammo or grip related.

saudadeii said:

Unless you determine the real cause, there's no guaranty that the parts ordered will fix it.

First, is it a new gun? Are you using the original mags? Does it do this with both mags?

What brand and bullet weight ammo are you using? Is it factory ammo or reloads?

Slide not locking back is a common grip related issue. During recoil, your thumb (or other part of your hand) can make contact with the slide stop preventing it from engaging. Try shooting a few mags one handed.

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It is relatively new though I’m through almost a 1000 rounds and the extraction problem has persisted. I was hopeful I was still “breaking it in”.
Using factory new 115 and 124 fiochi and Ytr now though I’ve ran through a couple other try outs at the range. All brass never reloads.
I have scoured the you tubes but the most recurring issue I saw was not enough spring pressure to the extractor and factory MIm extractors geometry not quite dialed in or something, I’m no expert though.
Slide lock problem does ring true for me since I have long lanky fingers and my thumb does rest higher up on the x carry and WC grip modules but not enough that I was paying attention to that, thanks I’ll keep that very in mind.

I would try some Winchester 124 gr. NATO before changing anything out. My M17 and M18 Commemorative pistols were stiffly sprung from the factory as they were optimized to work with full power combat loads.

I own 7 P320 pistols including one I built from new in the bag factory SIG parts and an FCU I purchased from someone who parted out a gun and have had no functioning issues, so I don't think there are any design flaws with extractor dimensions, maybe try replacing your extractor and extractor spring with new parts from SIG.

I am leary of aftermarket parts, many are very good but there are some out of spec parts out there.

CAR said:

I would try some Winchester 124 gr. NATO before changing anything out. My M17 and M18 Commemorative pistols were stiffly sprung from the factory as they were optimized to work with full power combat loads.

I own 7 P320 pistols including one I built from new in the bag factory SIG parts and an FCU I purchased from someone who parted out a gun and have had no functioning issues, so I don't think there are any design flaws with extractor dimensions, maybe try replacing your extractor and extractor spring with new parts from SIG.

I am leary of aftermarket parts, many are very good but there are some out of spec parts out there.

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Haven’t tried win. Yet thanks for the tip. I will try to hold out on replacing any parts until I test some more ammo.

Also, make sure your slide rails and barrel are lubed, I use G96 Synthetic Gun Oil on my P320s.

My grip is usually the culprit for the slide not locking back on empty. I am training it out of my stupid Glock hands but it is an issue. As for the FTE's, the prior advice seems sound to me!

Did you have extraction issues and slide issues before you changed your grip to WC.

cmdrcody said:

Did you have extraction issues and slide issues before you changed your grip to WC.

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Strangely enough I had about the same amount, even maybe more with the stock module. Probably had roughly 10 ftes per every 200 rounds shot, it’s a rough math since I wasn’t really looking for problems so I wasn’t keeping great tabs on it, only when it became apparent did I start counting. And the way my math works is about one fte every two mags.

FouledAmmo said:

Strangely enough I had about the same amount, even maybe more with the stock module. Probably had roughly 10 ftes per every 200 rounds shot, it’s a rough math since I wasn’t really looking for problems so I wasn’t keeping great tabs on it, only when it became apparent did I start counting. And the way my math works is about one fte every two mags.

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This sounds more generous than what it might be but still, that still a **** ton.

Update:
Winchester 115 ammo. 100 shots. No fte.
Also same range day
Cheap Turkish “YTR” 115 ammo. 200 shots. No fte.
Also me: going ******* insane cause my weapon is not cooperating with testing.
Sorry just venting, carry on.

stay safe y’all

I find my M18 is more particular about ammo than my M17 and x-5 320's.
It is obviously spring stronger than the longer slide guns.
Nato always runs, my hand loads that are made for uspsa competition run, though the ejection is only 3-5 ft away from the gun.
There are few recoils spring options for the M18 yet.

I've also found the more I shoot it the more reliable it is with the cost effective Win white box type ammo

First place to look when the slide won't lock back is... the magazine.

I had a new Sig magazine that had a very low "shelf" on the follower, compared to all of the other mags I own. The shelf is the part of the follower that pushes the slide release upwards into the notch on the slide. Check and compare your magazines to look for that flaw, and any other flaws related to the follower perhaps not functioning smoothly, and keep track of them individually to see if you can identify or relate the problems to just one of the mags.

Second place to look with feed problems is... the ammo. So switch to another brand and give that a try.

Third place might be the recoil spring assembly. If that is actually the case, the problem might go away as the spring breaks in. Although I don't like that thought, since it should work right from the start.

Good luck!

Update.
Still same ammo, since it’s dropping price more will follow but for now running through this Turk turd.

replaced the extractor spring PIN purchased part from sig (“extractor pin Plus”).. Not the extractor nor the spring. Ran through 200 rounds. No FTE!
that’s a good sign.

slide lock back problem persists, paying special attention to thumb placement and not hindering slide lock operation. (Fun fact, just got a p365 that I broke in the same day and same problem occurred).. at this point I’m leaning towards someone’s comment on 115 g ammo not packing enough punch to lock it back but I’m no expert so, maybe?

either way, I’ll post some results after this order of 124 g ammo comes in. At least one of the main issues seems to have gone away.

As always, stay safe.

I had two P320 pistols develop failure to extract. One was several years old with thousands of rounds through it and the other was about a year old with a few hundred or rounds through it. Sent them back to Sig and they replaced the extractor assembly. Fine for a little over a year and then the problems started again. Sig wouldn't take them back this time. I read on-line of a rolling change to the extractor assembly and ordered new parts from MGW. Both pistols have been flawless with many many rounds through both.

Alpo said:

I had two P320 pistols develop failure to extract. One was several years old with thousands of rounds through it and the other was about a year old with a few hundred or rounds through it. Sent them back to Sig and they replaced the extractor assembly. Fine for a little over a year and then the problems started again. Sig wouldn't take them back this time. I read on-line of a rolling change to the extractor assembly and ordered new parts from MGW. Both pistols have been flawless with many many rounds through both.

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I know some of you will say, try one variable at a time, and I appreciate the input and advice guys. I’m just going to tell you the sequence of events and results.
…
So I changed the extractor spring pin to an extractor pin plus. And over 200 rounds of 115 I did not have FTEs. Getting expensive. But after changing up to a 124 grain I had ONE out of a 100 rounds not extract.
One more round of 200 (124g) with a new skeletonized wolf extractor, and the last of my ammo alllowance (124g) as per my wife; NO FAILURE!.
Now I’m going to try stock everything and 124 grain (Winchester this timeno more Turkish range day ****)..
I guess I’ll wait until Xmas bonus (if we have one) and run through some more ammo to corroborate.
I also noticed I rub line on the interior portion of the slide. Is this a thing!?