1026 Retaining Ring

If you have worked on a S&W 3rd gen framed mounted decocker pistol, you have probably noticed the hammer pin has a retaining ring that is a pain in the you know what to install, and after I took mine off and put back on a couple times was bent and spread open enough that I wanted to keep a few spares on hand. BMCM was nice enough to give me a part# (902830000) for the 1026 retaining ring and also show me a tool he made for installing them. When I was searching for them online, I found there was another retaining ring that might also work for this application. It is a different type of ring that is easier to install and more available in stock online. It is a part made for the M&P 380 Shield EZ. I thought that it might work on the 1026 hammer pin, so I ordered one to try out. Below are pictures of both rings. I have not taken the gun to the range since I have installed this ring. I will try to make it to the range next week and update this thread. I have used this type of retaining ring many times on machinery and I believe it will work good on this pistol. I'm not saying that one ring is better than the other and I'm not trying to convince or advise anyone to use the M&P Shield retaining ring. I am just showing what I am doing and I believe for purposes similar to mine, this is useful information. I have not tried this part on a 9mm frame mounted decocker pistol because I don't have one.

This is what the S&W oem 1026 retaining ring looks like.


This is the M&P 380 EZ Shield retaining ring installed on the 1026 hammer pin.


It is true that the grip among other things will keep the side plate and hammer pin from backing out of the frame but on frame mounted decocker guns it is more important that this pin stays all the way in tight to the frame to keep the decocking lever and pawl meshed together. In this picture below, the ring looks bowed up almost like it doesn't fit properly, or bent. This applies pressure down on the frame and will assist in keeping the ring from coming off of the pin, and also keep the pin and side plate pulled tight into the frame, keeping the decocking lever and pawl meshed together tight.


I put the ring on the pin in the 6 o'clock position so that it is below the top edge of the grip.


MWGW M&P 380 Shield part# 3005540


Numrich M&P 380 Shield part# 687270

Looks like a good workaround. Thanks for your post on this. We are definitely on our own now in terms of the 3rd generation pisols.


Carter

The second type of clip you show is called an "E" clip. They are an auto part generally found on carburetors. If you take a sample to an auto parts store they should be able to provide these for about ten cents, on even free!

Alk8944 said:

The second type of clip you show is called an "E" clip. They are an auto part generally found on carburetors. If you take a sample to an auto parts store they should be able to provide these for about ten cents, on even free!

Click to expand...

That's good to know! I was thinking about trying to get a size or part# to get a bag of them from fastenal or mcmaster-carr, but I don't use enough of them to go that route. I already ordered 3 more from Numrich and that's probably all I will ever need, but the auto parts store is a good option.

Deformation of the retaining ring like depicted above is a clear indication the ring is not properly sized to the shaft or groove diameter.
It will not stay put for long. I appears to me that ring is too thick for the groove width.

Retaining rings are sized based on industry standard criteria; Shaft diameter - Groove Diameter - Groove Width.

Unfortunately S&W went with a non-standard size that cannot be had from any industrial supplier. Further, since the only way to get the factory ring off is by destroying it, S&W clearly didn't want owners of these post recall guns taking things apart.

It would have been nice if they had selected a ring one could use, oh let me see, Hmm, perhaps a pair of retaining ring pliers on?
So as to safely remove it without destroying the thing? Hmmm?

But, I digress...
So for retaining ring sizing here's what you're looking for, a ring that fits this shaft...

Shaft diameter 9/64 inch or 0.140625"
Groove Diameter is 1/8 inch or 0.125"
Groove Width is barely 0.022" that's twenty two thousandths of an inch

After a good deal of searching, emails & phone calls, the only external retaining rings I have identified that fit the hammer pin other than the factory 90238 part is a metric ring sized for a 4mm shaft which is McMaster - Carr part number 90119A106.

So, our shaft here is 9/64" or about 3.57mm and that ring is sized for a 4mm shaft.
But what's most important is the groove diameter it is meant for which is 3.2mm or 1/8 inch
And the ring thickness meets our application as well being a little under .5 mm which is around 0.019"
That ring snaps onto the groove in our hammer pin with authority and holds quite well.
While I prefer using the factory rings, the supply of those will dry up so, I see these as a viable alternative.







One other thing...
When using a retaining ring in this application, a ring with an open sector, I would orient the open sector facing forward towards the muzzle. Thereby reducing the possibility of recoil inertia forces dislodging the ring.

Cheers
Bill

BMCM said:

Deformation of the retaining ring like depicted above is a clear indication the ring is not properly sized to the shaft or groove diameter.
It will not stay put for long. I appears to me that ring is too thick for the groove width.

Retaining rings are sized based on industry standard criteria; Shaft diameter - Groove Diameter - Groove Width.

Unfortunately S&W went with a non-standard size that cannot be had from any industrial supplier. Further, since the only way to get the factory ring off is by destroying it, S&W clearly didn't want owners of these post recall guns taking things apart.

It would have been nice if they had selected a ring one could use, oh let me see, Hmm, perhaps a pair of retaining ring pliers on?
So as to safely remove it without destroying the thing? Hmmm?

But, I digress...
So for retaining ring sizing here's what you're looking for, a ring that fits this shaft...

Shaft diameter 9/64 inch or 0.140625"
Groove Diameter is 1/8 inch or 0.125"
Groove Width is barely 0.022" that's twenty two thousandths of an inch

After a good deal of searching, emails & phone calls, the only external retaining rings I have identified that fit the hammer pin other than the factory 90238 part is a metric ring sized for a 4mm shaft which is McMaster - Carr part number 90119A106.

So, our shaft here is 9/64" or about 3.57mm and that ring is sized for a 4mm shaft.
But what's most important is the groove diameter it is meant for which is 3.2mm or 1/8 inch
And the ring thickness meets our application as well being a little under .5 mm which is around 0.019"
That ring snaps onto the groove in our hammer pin with authority and holds quite well.
While I prefer using the factory rings, the supply of those will dry up so, I see these as a viable alternative.

View attachment 897054

View attachment 897055

View attachment 897057

One other thing...
When using a retaining ring in this application, a ring with an open sector, I would orient the open sector facing forward towards the muzzle. Thereby reducing the possibility of recoil inertia forces dislodging the ring.

Cheers
Bill

Click to expand...

Good information, thank you. I am going try these M&P Shield retaining rings since I already have them, but I will definitely get some of those from McMaster-Carr if these don't stay on.