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Seeking stupidity relief: P320 FCU stuck on slide. (Don't remove the takedown lever first!)

This topic can be found at:
https://sigforum.com/eve/forums/a/tpc/f/430601935/m/6910085464

December 21, 2019, 07:24 PM
sigfreund
Seeking stupidity relief: P320 FCU stuck on slide. (Don't remove the takedown lever first!)
I had to deal with not one, but two—count ’em, two—such incidents today.

If one removes the P320 takedown lever before removing the slide, the fire control unit comes along with the slide when it’s lifted up, and then they can’t be separated.

I don’t recall ever reading about such bone-headedness here, but considering how difficult it was to rectify the mistakes, I wonder if it’s just something I missed, and, more important, if anyone knows of a quick and easy way to correct the problem that didn’t occur to two geniuses. (FWIW, trying to move the FCU forward/back on the slide did not work.)

And did I mention: don’t remove the takedown lever before removing the slide? If not, don’t.

This message has been edited. Last edited by: sigfreund,




6.4/93.6

“Wise men talk because they have something to say; fools, because they have to say something.”
— Plato
December 21, 2019, 07:36 PM
RHINOWSO
Yeah, it's a motherfucker to remove.

I did it while reassembling and forgetting to put the TDL back in.

Like you, I corrected it with much cursing but simply vowed to never do it again, which is easy now since I don't own a P320 anymore, so I never figured out an 'easy fix'.
December 21, 2019, 08:57 PM
Modern Day Savage
While I've had the opportunity to shoot both the P250 and the P320 I've never owned either, never field stripped either...and know just enough about their mechanical function to be dangerous, and probably shouldn't even be posting about them...having said that, I thought that the two shared some similarities.

If so, then I recalled this thread and thought it might help. If not, then I would welcome a correction.

Messed up my P250
December 21, 2019, 09:32 PM
BuddyChryst
Well that’s interesting. I feel like I’d have to recreate the issue to help resolve it, but if you can’t figure it out, that wouldn’t bode well for me.

My initial thought is that the takedown lever pushes the mag safety as it rotates. Perhaps with the takedown lever removed it re-enables the mag safety and won’t let things happen? I dunno.

ETA: I’m trying to think what would hold the slide to the FCU and the only thing coming to mind would be the sear. If keeping the trigger pressed while trying to slide doesn’t work, I’d try to move it back like I was locking back to start takedown, lift the slide catch and try to get the takedown through to rotate it.

Probably stuff you’ve already tried. I dunno.


------------------------------------------------
Charter member of the vast, right-wing conspiracy
December 22, 2019, 12:18 AM
sleepla8er
.

Hi SigFreund ~ It's been a couple of years since I fixed this problem for someone at a local range. It won't be until after New Years that I will have a P320 in hand to use as a test bed to verify that I'm remembering the fix correctly.

The hang up is the normal position of the Striker Pin protruding from the slide downward and being held by the resting position of the Sear in the FCU. You can see this with the FCU out of the Grip and lining it up with the slide.

The fix...

Need to add a step, you had better be damn sure there isn't a live round in the chamber before you follow these directions.

Reinsert the stuck FCU and Slide onto the Grip Module.

Rack the Slide to the rear slowly.

Slowly push the Slide forward until you feel the Striker Pin barely make contact with the Sear.

With the pistol pointed in a safe direction, slowly pull the Trigger to lower the Sear. Don't reset the Trigger or the Sear will return to it's resting position.

Slowly push the Slide forward when you feel the Sear has lowered and the tension on the Striker Pin is gone.

Inspect the Sear and Striker Pin for damage and replace as appropriate.

.

This message has been edited. Last edited by: sleepla8er,
December 22, 2019, 07:59 AM
sigfreund
Thanks much, sleepla8er, for that. It was obvious that something was preventing movement of the slide on the FCU, but I couldn’t figure it out at the time and was focusing on what ultimately allowed us to correct the problems. I will print out your guidance and keep it handy, at least as a reminder to not do that same stupid thing again.

And thanks for the other comments as well. As always, this is a great source of information regardless of how much we may think we know.




6.4/93.6

“Wise men talk because they have something to say; fools, because they have to say something.”
— Plato
December 22, 2019, 12:45 PM
sleepla8er
.

Sigfreund, you are most welcomed! Over the years, I have always found your posts to be most informative.

Also, I went back and added in red text what I've always considered a no brainer of ensuring pistols are unloaded before disassembly.

I've had guys bring me a pistol saying whatever isn't working then stand there shocked when I remove a live round with a dumb look on their face ~ and an irritated look on mine!

.
December 31, 2019, 05:59 PM
sleepla8er
.

While on YouTube today, I came across this video about the P320 FCU and Slide hung up when reassembled without the Takedown Lever being installed first.

Please note:
Unlike what I & Sigfreund encountered, the slide in this video would not move at all.



Direct Link to YouTube:
December 31, 2019, 11:06 PM
arcwelder
Perhaps a silly question, but why remove the TD lever? Why not just rotate it as normal?


Arc.
______________________________
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January 01, 2020, 01:07 AM
92fstech
quote:
Originally posted by arcwelder:
Perhaps a silly question, but why remove the TD lever? Why not just rotate it as normal?


I imagine someone was probably getting ahead of himself when cleaning and simply skipped a step. I always remove the FCU when I clean my p320 and scrub it with solvent and spray with brake-clean before lubing contact points. However, I always remove the slide first before I pop the takedown lever out to remove the FCU...skipping this step will apparently result in the problem described by the OP.
January 01, 2020, 08:52 AM
sigfreund
quote:
Originally posted by 92fstech:
skipping this step will apparently result in the problem described by the OP.


Yes, it will, as when changing grip modules, replacing the trigger, or disassembling one’s gun in the attempt to determine what is causing the problem in another gun. Roll Eyes

Einstein didn’t say it any more than some of the other things attributed to him, but the expression that starts, “Doing the same thing and expecting different results …,” immediately comes to mind after realizing what has just happened.

And as stupid as the trick is, there is actually a somewhat rational reason for why we might do that: I am disassembling the gun with the intention of doing one of the above things like replacing the trigger, so I lock the slide back and turn the TDL in preparation to removing the slide as usual. But because I know that the lever will have to be removed to get the FCU out, why stop with just rotating the TDL? Why not just continue the process while I’m at it? So that’s how it can happen and not seem so stupid at the time.

But to reiterate the tech tip, boys and girls: If you need to remove the fire control unit from your P320, take the slide off the gun as the second step (after ensuring the gun is unloaded), and definitely before removing the takedown lever.




6.4/93.6

“Wise men talk because they have something to say; fools, because they have to say something.”
— Plato
January 01, 2020, 02:21 PM
DirectDrive
Helpful thread.

The P320 is different for me.
Etched in my brain is that completely removing the takedown lever is for removing the FCU.
Removing the slide the slide is like many other designs.

But you never know when a giant brain f@rt might happen.
October 07, 2020, 06:36 PM
George from Alaska
Thanks so much... I've been gently wrestling with one of my 320s for a week to solve this. Was literally going to shame myself and send it in to Sig when I did a research and your help came up.
Thanks again... George

quote:
Originally posted by sleepla8er:
.

Hi SigFreund ~ It's been a couple of years since I fixed this problem for someone at a local range. It won't be until after New Years that I will have a P320 in hand to use as a test bed to verify that I'm remembering the fix correctly.

The hang up is the normal position of the Striker Pin protruding from the slide downward and being held by the resting position of the Sear in the FCU. You can see this with the FCU out of the Grip and lining it up with the slide.

The fix...

Need to add a step, you had better be damn sure there isn't a live round in the chamber before you follow these directions.

Reinsert the stuck FCU and Slide onto the Grip Module.

Rack the Slide to the rear slowly.

Slowly push the Slide forward until you feel the Striker Pin barely make contact with the Sear.

With the pistol pointed in a safe direction, slowly pull the Trigger to lower the Sear. Don't reset the Trigger or the Sear will return to it's resting position.

Slowly push the Slide forward when you feel the Sear has lowered and the tension on the Striker Pin is gone.

Inspect the Sear and Striker Pin for damage and replace as appropriate.

.



P220 European
P220 Scorpion
P220 10mm Legion
MK25
P226 Legion
P226 SAO Legion
P229 Legion
556 rifle, my favorite 556
P320 M17 (not the expensive
one) with Leupold DPP
P227 Tac-ops
machineguns
suppressors
07/02
October 07, 2020, 06:51 PM
sns3guppy
You can also just remove the rear cover plate and striker assembly.

You're the only person to have ever pulled off the slide and FCU together after removing the takedown lever...

Not.
October 07, 2020, 09:48 PM
sigfreund
quote:
Originally posted by sns3guppy:
You can also just remove the rear cover plate and striker assembly.


Definitely good to know and would be far easier to remember if I didn't have the full instructions above.

Hopefully it will never happen to me again, but I do get calls for help. Thanks!




6.4/93.6

“Wise men talk because they have something to say; fools, because they have to say something.”
— Plato
October 07, 2020, 10:15 PM
sns3guppy
If it makes you feel any better, I've done it a few times. Thinking about something else, popped the lever out, thinking I'd just slip the slide off like everything else.

Once is a mistake. Multiple times...
October 09, 2020, 07:46 PM
SigLaw
I just did the same stupid thing today, changing the grip to the Wilson and did not put the takedown lever in. I followed the video posted above and it worked for me. It took me a couple of tries to find the right spot but it did work and I was able to replace the grip.


________________________
"Don't mistake activity for achievement." John Wooden, "Wooden on Leadership"
October 10, 2020, 12:59 AM
Jester814
As somewhat of an aside here, is it possible to pop the lever out without rotating it down first?


________________________________________________
October 10, 2020, 07:26 AM
sigfreund
quote:
Originally posted by Jester814:
As somewhat of an aside here, is it possible to pop the lever out without rotating it down first?


Yes, if the slide is removed.
If not, though, then no because removing the takedown lever out of the frame and grip module is prevented by the recoil spring guide (rod).




6.4/93.6

“Wise men talk because they have something to say; fools, because they have to say something.”
— Plato
October 10, 2020, 08:54 AM
Oat_Action_Man
Well I'm glad I read this thread. I wouldn't have even conceived of the problem without reading this.

Not that I expect to encounter it, but it's good to at least have this in the back pocket before I blow a gasket if it does.


----------------------------

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