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Alright need some help in here.


RangeJunkie

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So here's what's up with my gun guys. I'll try to be as detailed as possible, ask any questions you need to.

STI Trubor in 9

Cheely 90 mount for Cmore

3 140's, 2 170's, 1 stock mag.

Stock extractor and ejector that are tuned (by a local, well known smith)

So here is what's up, gun ran 99.99% of the time with the old set up I had. It was a traditional STI mount and untuned mags.

I decided that wasn't reliable enough, and went with a Cheely 90 mount as well as tuning my mags per Dawson video with his tuning kit.

I don't know what I did, but now the gun will not cycle correctly at all. I know for certain the screws are the correct length in the dust cover and it is no longer dragging. I took a dremel to the inside of the dust cover to ensure it was flush.

Whether I have a loaded, empty, and even NO mag at all in the gun now I have these symptoms.

After firing, the extractor will hold onto the spent case but not eject it at all. It will actually insert the spent case back into the chamber. It doesn't double feed or anything. Once I rack the slide manually the spent case makes a clean hit with the ejector and sends the case ejecting like it use to.

This happens on major and minor loads and they haven't changed in any recent time.

Major = 7.2 Autocomp with a MG124JHP

Minor = same bullet with 5.5 of AC

So I'm in quite a situation here guys. I'm not sure why adjusting this two things have turned the STI into this.

My smith is swapped and won't be able to look at it for a couple weeks.

Recoil spring has been 7lbs for the last 3k rounds and ran as I said before really well.

Also, I've noticed that my mags will not drop free as easily after being tuned.

Let's hope you guys can help me..I'm loosing my mind not shooting!

Bare with me, I jumped from Production to Open this year and it's been a big learning curve in every way.

Thanks!

Edited by RangeJunkie
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I saw somthing similar to this recently and it turned out the reverse recoil plug was cracked, as a result when the gun was fired did not cycle far enough and re-inserted the empty brass and then the shooter would rack it out and fire another round. However in this case it was not 100% single shot but darn near.

By the way, recoil springs don't last forever in an open gun, they only last at most 5K rounds. IMHO

I switched from limited 3 years ago, still transitioning and learning.

The more bizare the problem the simplier the solution most of the time, that why its so hard to figure out.

Edited by CocoBolo
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It could be any number of things .... Spring, cracked grip, loose grip screw, etc.

Try changing the spring, maybe even a stronger spring just for experimentation. But also check your grip screws. Sometimes when you tighten one thing something else loosens.

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Just replaced my old wolf 7lb spring with an ISMI

One other important note is why I was undercutting and putting grip tape on the grip I did notice one of my grip screws were broke. But it was an interesting break.

Imagine the half moon was broke off inside the grip leaving you with just the threads attaching to the screw.

So the grip screws are newly blue locktite'd and tight.

Other ideas? Thank you so much guys

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For what it's worth I did try to bump up to an 8lb spring. It put the gun in battery more easily but still had the same issues so I decided to go back to the 7lb to try to isolate the problem.

I'm going to check the recoil plug now

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Yeah I was just going to say, I tried to get my gun to run on a 7lb spring years ago, and even though it would .......... it was also liable to have some sort issue every 500-1000 rounds. Not to mention with a 7lb spring I had to replace the spring almost every month (approx. 1000-2000 rds)

But once moving up to an 8lb spring I could go 3-6 months on 1 spring.

Edited by Chris Keen
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Yeah I was just going to say, I tried to get my gun to run on a 7lb spring years ago, and even though it would .......... it was also liable to have some sort issue every 500-1000 rounds. Not to mention with a 7lb spring I had to replace the spring almost every month (approx. 1000-2000 rds)

But once moving up to an 8lb spring I could go 3-6 months on 1 spring.

Same here Chris. I went against Matt's advice and tried a 7. It felt better to me but unless the gun was spotless it was unreliable. Like you said, only a few matches and it would have an issue. Amazingly the 8 runs just fine even dirty.

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Went out and tried it some just now. Ran through 3 rounds then jammed. I have pics of the different types of jams if someone could help me posting.

I just moved into my new house and do not have internet, I'm on my phone doing this. If someone would possibly let me shoot them an email we can get some pics in this thread.

So I also tried some more extractor tension, same issue. Dialed it back some, same exact issue.

Seems to be doing two of the same style jams repeatedly. Thank you guys for your help so far.

For what it's worth; I've tried my minor and major loads and a friends 121MG with 7.4 of AC tonight just to try to figure things out to no avail.

Also, I noticed that on one of my mags as I cycle the slide with no ammunition in it at all I notice some drag at the last half an inch as it goes into battery. Maybe that has something to do with it.

Thanks guys!

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Missed that.

Something's dragging if it's not cycling fully, which sounds like the issue if it's not hitting the ejector.

Is it possible the last scope mount screw (closest to the slide stop) is too long? You might not see evidence of it on the slide's spring tunnel, and the way you rack the slide, if the fit's a little loose, could tweak things enough so that the problem isn't replicated when hand-racking.

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My first response would be no, but I could take that one out and shorten it some. My friend down the street (literally, and I know this sounds odd) just changed his mount on his GM from a stock STI to a 90 like mine and I know for a fact his screws are longer than mine stick into the dust cover.

Yet his functions 100%..

Missed that.

Something's dragging if it's not cycling fully, which sounds like the issue if it's not hitting the ejector.

Is it possible the last scope mount screw (closest to the slide stop) is too long? You might not see evidence of it on the slide's spring tunnel, and the way you rack the slide, if the fit's a little loose, could tweak things enough so that the problem isn't replicated when hand-racking.

Edited by RangeJunkie
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No worries.

Looks like it's hitting the ejector to some extent, else they wouldn't be pointing up like that. Just not enough to get them out from underneath the extractor completely.

Remove the recoil spring assembly and see what the slide action feels like.

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It's a standard length (ill have to get the calipers out to verify, my smith tuned that) STI with an interesting profile on it.

Picture a slant going inward from the left side to the right side toward the chamber. It doesn't have the typical brazos cut or anything such as that.

I do have a spare that is (or was if it is actually broken) tuned to be exactly as the original I could try

How long is your ejector? Is it an extended ejector?

I've seen ejectors that didn't look broken, but in truth the tip was broken off just enough to cause a problem only 5% of the time.

Edited by RangeJunkie
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My guess is the ejector. I would get a Brazos tuned ejector and an Aftec extractor and be done with it. I have that set up in my SteelMaster and it runs flawlessly, but before I went with that set up I could not get through 30 rds without a malfunction. I also got a new Edge a while back and installed that set up before ever firing the pistol and have never had a malfunction ever.

Just my experience,

SR

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Based on what you said

(1) The gun ran 99% with stock STI mount and Mags.!

Most of the time--moving to a side mount allows the gun to run 100% eliminating the sometime stove pipe .

First step! Take off the mount and fire the gun--- If problem is still there. You have an EJECTOR/EXTRACTOR RECOIL SPRING (based on 7LB use) issue.

A Brazos tuned extended and a new AFTEC (installed correctly!) will probably fix the issue.

I doubt you have a mag issue.

A 9LB recoil spring is normally VERY reliable for an entire season!!! 7LBs just don't work and 8lbs somethime work.(but not very long)

RULE ONE: Only change one thing at a time when upgrading or testing new Open gun configurations!

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