SIGforum
Rare failure mode

This topic can be found at:
https://sigforum.com/eve/forums/a/tpc/f/150601935/m/8540023224

April 07, 2017, 09:10 AM
P320Mac
Rare failure mode
New pistol - was unable to remove slide for cleaning and lubrication. Looks like a rare failure mode.

Can happen with pistols using "Glock" scheme of pressing down two tabs on opposite sides of frame that should allow slide to move forward and off of frame. Seems only to apply to pistols with full length recoil-spring-rods that are closed at the rear (rather than the more common, front). Not expected to apply to such rods that are welded at both ends, only to rods that have a detachable end that is normally adjacent to barrel lug.

If the detachable end becomes detached/loose, it will/can block removal of slide. Suggestion is to check even new pistol's ability to be disassembled and to note if pistol's rod falls into the above, narrow class.

It is well known to have rods with a detachable end (so that one may test different springs or replace springs) that is forward. Such a detachable end may be checked with ease just by racking and locking the slide back. Not so when the detachable end is on the back of the rod.

Factory suggests enough force to be applied to rear of slide to break free obstruction. This in a brand new pistol. Mac


Mac in Michigan
April 07, 2017, 09:48 AM
flesheatingvirus
Need more detail on your failure, not the failures other pistols are known for.

What exactly is happening? Did you remove it previously, such as for the initial clean/lube after purchase?

Also (have to ask), did you read the manual?

Did you check other threads that may give you some information?
https://sigforum.com/eve/forums...0601935/m/3040060224


________________________________________

-- Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past me I will turn the inner eye to see its path. Where the fear has gone there will be nothing. Only I will remain. --
April 07, 2017, 10:40 AM
P320Mac
posted April 07, 2017 09:48 AM
Need more detail on your failure, not the failures other pistols are known for.
** Too broad a request.

What exactly is happening? Did you remove it previously, such as for the initial clean/lube after purchase?
*** Slide will only move forward during the disassemble phase about 1/8 inch.
*** Slide was not removed "previously."

Also (have to ask), did you read the manual?
*** I read the manual. Used both the scheme for slide removal suggested in manual and the scheme that has worked on other pistols with the same arrangement. Also examined the provided exploded diagram fully to understand parts and their relationships.

Did you check other threads that may give you some information?
https://sigforum.com/eve/forums...0601935/m/3040060224
*** No. URL provided is for a pistol of a different type. Limited to pistols where pressing down two tabs on opposite sides of frame allow slide to move forward AND having full length recoil-spring-rod AND the rod having a detachable end at its back (barrel lug touching end).

Main point is that such pistols need to be checked for looseness of the rod's detachable end. Mac


Mac in Michigan
April 07, 2017, 03:29 PM
flesheatingvirus
You didn't specify the type of pistol in the original post, so I assumed it was a 320 based on your name.


________________________________________

-- Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past me I will turn the inner eye to see its path. Where the fear has gone there will be nothing. Only I will remain. --
April 07, 2017, 04:25 PM
P320Mac
Not P320.

Received repair parts from manufacturer to deal with the expected result of applying sufficient force to remove slide.


Mac in Michigan
April 07, 2017, 07:38 PM
hjs157
Mac. Are you asking for or giving advice? In either event, your post is somewhat nebulous. If you are asking for advice, some of the most knowledgeable folks in the business hang out here and are more than eager to assist. If you are giving advice, many of us would like to learn from your experience. It would be very helpful if we at least knew the make and model of the pistol to which you refer. Thanks.
April 07, 2017, 09:43 PM
P320Mac
My goal is to note a rare failure mode and to suggest that:
1. when one has a pistol with detachable end on the back of the recoil spring's rod (and this is rare) one should continually check the detachable end's security; and
2. when designing a recoil spring system, reason exists either not to have a detachable end or to have the detachable end on the forward part of the rod.

[I add that rods with a detachable end in front, and I have used them, also need to be checked. Checking is easy when the slide is locked back.]

Everyone here can know if the rod in a particular pistol might have this latent issue. Some pistols do not have what one could even call a rod (see old 1911 and even the newest Colt 1911 with two loose, nested springs.)

One designing a new pistol may not understand some failure-modes nor the history of development (with special attention to failures) and have a need to do things in a different manner.

A look at the pieces after breaking free the slide may tell more. I sure do not like applying force as manufacturer has recommended.


Mac in Michigan
April 08, 2017, 05:18 AM
fjgiie
Sounds like the aftermarket for the P232. Use grease for this problem.
April 09, 2017, 09:33 AM
rscalzo
quote:
Sounds like the aftermarket for the P232. Use grease for this problem.


Grease will not sure that in the 232. It's also not that rare. Unfortunately, the slide lock requires a specific press to reinstall.

Still have no idea what the OP is requesting. Best I can f9igure is a improper reassembly of the guide rod and spring assembly.


Richard Scalzo
Epping, NH

http://www.bigeastakitarescue.net
April 14, 2017, 12:09 PM
P320Mac
After quite a few days of detective work and the assistance of helpers this is the final result:

In a PPQ type action, the disconnector part of the trigger bar needs to be gently pushed aside while mounting slide. In the subject pistol, with a more-than-PPQ tightness between slide and frame, dealing with the disconnector required rather more effort. . . .and the disconnector needed a very small amount of adjustment. It ended up that this had nothing to do with the difficulty in removing the slide.

What seems to have happed is that using a Glock like disassembly technique and the fact that the recoil-spring's rod is at a slight angle and that the rest-cut in the barrel for the end of the rod is very shallow resulted in the end of the rod jumping right to the major barrel lug, which interfered with slide removal.

The slide removal technique that works is to:
1. remove magazine
2. clear chamber
3. close slide
4. pull trigger
5. grab the frame with both hands and point pistol down (do not touch the slide)
6. using both thumbs, depress take-down tabs at the same time all of the way down
7 see gravity remove slide.

I would have designed the rod's end and the barrel's rod-rest/cut so that technique was not so important. Almost every pistol has some sort of unique feature/bug.
Thanks for help.


Mac in Michigan