Looking for some help with weird TSO .40 feeding problem

[Guitarmageddon]

Hello everyone, scratching at this weird feeding issue with my TSO. Out of the blue, it had a few random failures to feed but in an odd way. It would apparently be getting a round into the chamber, but somewhere on its way there, it would bind up and the slide would be stuck about half way like you see here. The magazine falls freely out when I release it. These are all new mag tubes I replaced at the beginning of the season, and for shiggles, today I put a new grams 11-coil spring/follower into one of the mags. I use CZC base pads as well. Up to this point, I don’t believe Ive had any non-self inflicted failures to feed in 7,000 rounds since February on this gun.

 

 

On an additional time after the above photo was taken, I caught that the firing pin retaining plate on the back of the slide was actually able to slide down and was catching on the hammer just barely. So Im not sure if that’s what the issue was all along,  but I had never noticed that before. I actually had to depress the firing pin back into the channel to slide the cover up. I use an extended pin and reduced power pin return spring spring, that is at least 7-8k rounds old. I thought to myself, perhaps the firing pin return spring was in a weakened state and wasn’t exerting enough pressure on the retaining plate, but that seems like quite a stacking of events. In any case, I threw a fresh reduced power return spring in it today. I also thought maybe there was a burr on the pin, or dirt in the channel, but they check out fine.

 

To recap some key points:

1.       I had an extra extractor and spare extra power extractor spring (also what I used before for the entire year so far), so I threw in the new extractor and fresh extractor spring today. I took them both out and inspected but couldn’t find any reason the old extractor would be inhibited.

2-      The mag tubes are all new this year, with grams 11 coil springs/followers that never skipped a beat until recently. For the hell of it, I replaced one of the tubes with new grams guts today, but I don’t suspect they can all be bad already, and at the same time on the same range visit….

3-       I  use a DPM systems 3-spring guide rod and its been great so far. Spring has only been used since feb, and has about that same round count on hit, roughly 7k.

4-       I load 180gr blues RNFP or 165gr blues, either weight to 1.131 COAL. Again, these combos have never skipped a beat.

4-       I can rack through a bunch of mags of dummy rounds at home and no issues happen.

 

Now that Ive laid out the dictionary, anyone have any thoughts? Scratching my head here about what would be occurring all the sudden.

Edited August 29, 2022 by Guitarmageddon

[Superkaratemonkeyfighter]

It can’t be getting a round into the chamber from the mag and the slide get stuck there. 

[Superkaratemonkeyfighter]

Slide stop pin ?

[Guitarmageddon]

1 minute ago, Superkaratemonkeyfighter said:

Slide stop pin ?

Recently replaced after the last one finally broke. This one appears totally fine.

[Guitarmageddon]

Ok threw in the new firing pin retaining plate today. God knows how many rounds beat down on the other one, and figured since I replaced the pin/return spring to test, may as well freshen this part up to. You can see that the firing pin back end obviously sits proud of the plate and is securely held in place. You can also see the few dings on the hammer where the plate was caught before I noticed what was going on. That is not a friction surface though, so only a cosmetic thing.

From the pics you can see minuscule differences in the measurements old plate vs new. The new is about .0010 thicker, and also slightly less tall. Which would indicate that the other probably pancaked out a bit and got thinner I guess. If this didnt work, then I guess the only other thing could be that the channel itself is too wide now, due to wear. And I cant of course add slide material back to the gun... so a trip back to CZ at that point.

Something else that occurred to me though: is it possible that a worn down weakened recoil spring, at the end of its life, allows the slide to move rearward with too much speed and this compresses the pin against the return spring in the channel so much so that this enables the pin retaining plate to slide down? Seems pretty far fetched to me though. Not sure what else could allow the gun to exhibit this behavior. Anyone have any thoughts? thanks

 

[HesedTech]

Does the round fall out when the slide sticks?

 

The only way for the firing pin retainer plate to slide off is for the pin end to be entirely in the slide. Did you check the firing pin for unusual wear? From your pictures it appears there's some wear indicating the hammer and the plate aren't square. Check the hammer retaining/pivot pin and the associated hole in the hammer for wear.

 

Also check the barrel and its retaining tab, where the slide stop retain pin goes through. While the metal should be harder than the pin it too could have unusual wear causing the barrel to jam as it unlocks or locks up. Did you make sure the locking tabs on top the barrel and associate slide are clean and free of wear?

 

Additionally the round should have slid up under the extractor claw as it fed. Your extractor spring or claw could also be worn. 

 

If you haven't done it already do a search for parts which tend to fail on CZs. The extractor and slide stop are on the list.

 

I hope you find the issue, strange issues like this drive me crazy.

[Guitarmageddon]

1 hour ago, HesedTech said:

Does the round fall out when the slide sticks?

Yes, when the slide jams in place there is one just freely in the chamber and slides right out. Its as if when the pin stop plate comes forward just enough to catch on the hammer and stop the process, the slide kicks the top rounds of the mag forward with enough ass to knock it into the chamber, but it cant grasp it on the extractor. I tend to think this is more a symptom than the problem itself.

As part of exploring what could have failed, I put a fresh extractor and extractor spring in the gun the first time it occurred, and that didnt effect anything.

 

1 hour ago, HesedTech said:

The only way for the firing pin retainer plate to slide off is for the pin end to be entirely in the slide. Did you check the firing pin for unusual wear? From your pictures it appears there's some wear indicating the hammer and the plate aren't square. Check the hammer retaining/pivot pin and the associated hole in the hammer for wear.

....Additionally the round should have slid up under the extractor claw as it fed. Your extractor spring or claw could also be worn. ....

The hammer fits tightly and has no side to side play in the gun. all that stuff seems secure to me. Additionally, I replaced the firing pin and spring entirely, with a brand new one. Pics below on a comparison with the old/new. I use an extended pin, and a reduced power return spring. Same combo as I used for all my rounds this year. Just fresh new ones.

 

1 hour ago, HesedTech said:

Also check the barrel and its retaining tab, where the slide stop retain pin goes through. While the metal should be harder than the pin it too could have unusual wear causing the barrel to jam as it unlocks or locks up. Did you make sure the locking tabs on top the barrel and associate slide are clean and free of wear?

All seems to be fine and free of burrs. The slide stop is new, within a month. I replaced it after the other one finally gave out. I included a pic of the one in the gun below, side by side a fresh brand new one to help compare.

Ive got a bunch of pictures notating your various callouts below. I also tried to use my borescope to get a picture of the pin channel, but had to take a "picture of a picture" since its a junk phone I use just for that job.

See anything Im missing?


 

[Superkaratemonkeyfighter]

Firing pin and retainer plate have nothing to do with it. 
im sure those plates vary. The wear in the hammer is from the poor machining of the old plate. I still would worry to much about that. 
Are  you sure your safety isn’t getting bumped on ?

Edited September 4, 2022 by Superkaratemonkeyfighter

[Guitarmageddon]

2 minutes ago, Superkaratemonkeyfighter said:

Firing pin and retainer plate have nothing to do with it. 
im sure those plates vary. The wear in the hammer is from the poor machining of the old plate. I still would worry to much about that. 
Are  you sure your safety isn’t getting bumped on ?

Hmm, that is a good suggestion. But, that would be really hard to do considering it is an extended safety and my strong hand thumb uses it as a ledge pretty tightly. And also I've got thousands of rounds through the gun without ever inadvertently bumping the safety. And all the sudden now I could be bumping the safety out of nowhere for no good reason? That's why I tend to think it's not an accidental safety nudge.

[HesedTech]

I looked over the wear in your pics, it's pretty normal and probably less than my CZ guns. So, if the slide is jamming back/getting stuck back then there has to be a bind somewhere in the action. Not sure what to add except to remove the barrel and see how freely the slide moves on the frame rails. Is your hammer spring and its spring rod are smooth and not binding, the metal shield in the mag well over the hammer spring undamaged, the sear and the sear cage clean, the safety retainers and spring clean and in place, and finally the barrel bushing to barrel fit normal? How about the trigger bar fit against the slide or crud under the sear cage?

 

That's about all the parts on the gun. I missed it if you wrote about a complete dismantling and cleaning of the gun. Yes everything (hardest spring to install are the trigger and sear) take apart, ultrasonic clean and reinstall. 

 

Try that if it doesn't work send the gun to CZ, Cajun, CZCustom for complete inspection and repair.

 

It is odd the cartridge gets loaded without the breech face.

 

When I shot Tanfoglio 40SW the breech face bottom was so sharp as it started feeding the round coming up the face edge would occasionally catch the next round about half way down the cartridge causing a misfeed and jam. Rounding the edge of the face solved that issue. In your pic of the breech face it does look like you have a sharp right corner on the bottom. It might only be the light, but it almost looks like a piece fractured off. That may be catching the next round or twisting the slide slightly?

 

Just a couple of ideas. let us know what the problem was when you work it out.

[Guitarmageddon]

16 hours ago, HesedTech said:

I looked over the wear in your pics, it's pretty normal and probably less than my CZ guns. So, if the slide is jamming back/getting stuck back then there has to be a bind somewhere in the action. Not sure what to add except to remove the barrel and see how freely the slide moves on the frame rails. Is your hammer spring and its spring rod are smooth and not binding, the metal shield in the mag well over the hammer spring undamaged, the sear and the sear cage clean, the safety retainers and spring clean and in place, and finally the barrel bushing to barrel fit normal? How about the trigger bar fit against the slide or crud under the sear cage?

 

That's about all the parts on the gun. I missed it if you wrote about a complete dismantling and cleaning of the gun. Yes everything (hardest spring to install are the trigger and sear) take apart, ultrasonic clean and reinstall. 

 

Try that if it doesn't work send the gun to CZ, Cajun, CZCustom for complete inspection and repair.

 

It is odd the cartridge gets loaded without the breech face.

 

When I shot Tanfoglio 40SW the breech face bottom was so sharp as it started feeding the round coming up the face edge would occasionally catch the next round about half way down the cartridge causing a misfeed and jam. Rounding the edge of the face solved that issue. In your pic of the breech face it does look like you have a sharp right corner on the bottom. It might only be the light, but it almost looks like a piece fractured off. That may be catching the next round or twisting the slide slightly?

 

Just a couple of ideas. let us know what the problem was when you work it out.

Thanks for the input indulging all the pics/ideas. I am considering taking one of the pin stops I have and peening the edge of it slightly to give it more meat in the channel on the back of the slide, and see if this resolves it. If not, then I guess that pretty clearly points to the pin binding in the channel which gives some better direction. Just trying to isolate as much as possible before the gun would potentially go out of commission to CZ or elsewhere, for 2 months or something.

[Superkaratemonkeyfighter]

Still confused on how the slide is getting stoped by the firing pin retaining plate ?

a video of the stoppage would help 

[Guitarmageddon]

18 minutes ago, Superkaratemonkeyfighter said:

Still confused on how the slide is getting stoped by the firing pin retaining plate ?

a video of the stoppage would help 

ill be firing, the gun will lock up, then I look down and basically see it in exactly this position. Replaced with a fresh pin return spring AND tried a new extended pin and it still did it. unless I replaced it with a defective fresh return spring. I got a new plate yesterday and havent had time to get to the range yet but im cautiously optimistic about it fixing the issue

Edited September 5, 2022 by Guitarmageddon

[Superkaratemonkeyfighter]

That’s is weird. 
your firing pin springs is the only thing that puts pressure on that plate. By keeping the end of the firing pin sticking out of the hole. 
may no time should the pin get hit so deep in the channel but the hammer as to come out of that retainer hole 
 

Edited September 5, 2022 by Superkaratemonkeyfighter

[Guitarmageddon]

1 hour ago, Superkaratemonkeyfighter said:

That’s is weird. 
your firing pin springs is the only thing that puts pressure on that plate. By keeping the end of the firing pin sticking out of the hole. 
may no time should the pin get hit so deep in the channel but the hammer as to come out of that retainer hole 
 

Yep totally agreed. And even with a whack from a non-reduced power hammer spring (aka "full power") would it even get near enough power to send it all the way down into the channel. I suspect maybe a defective Cajun reduced power return spring. Part "90741". I have another fresh NIB one . Will compare.

[Superkaratemonkeyfighter]

Put a stock one in. 
I still use what ever came with the TSO 

If it’s reduced power Idk but it’s the longer length one. 
I’m not a fan of those really short ones. 

[Guitarmageddon]

1 hour ago, Superkaratemonkeyfighter said:

Put a stock one in. 
I still use what ever came with the TSO 

If it’s reduced power Idk but it’s the longer length one. 
I’m not a fan of those really short ones. 

Yea I got a few of the regular strength ones I'm going to give a try with. Will report back. Could have been s#!tty luck that I had a spent return spring then replaced with a new defective spring, but I wouldn't write it off.

[Guitarmageddon]

Hey folks wanted to close the loop on this one. Some combo of the replacement CGW reduced power firing pin spring (97041), and replacement firing pin stop plate, fixed the issue. I tend to lean towards it was the return spring, but theyre both cheap enough parts and the gun had enough miles on it that I just replaced both. That was a first for me.... thanks to everyone that gave their input and assistance on this one.