1911 Slide Stop Plunger

[Koda94]

What is the distance the slide stop plunger is supposed to protrude from the plunger tube with no slide stop in place? Measured from the end of the plunger tube to the tip of the spherical radius on the end of the slide stop plunger at rest.


The reason I'm asking is because mine protrudes far enough that the spherical radius on the end is well past the ramped surface on the slide stop preventing it from depressing the plunger during assembly, the only way is to use a tool to manually depress the plunger into the frame a bit.

 

[Don P]

Try this from the 1911 forum. Photo in post #405
https://forums.1911forum.com/showthread.php?t=214653&page=17

 

[4V50 Gary]

I don't think the plunger is sticking out too far.

Rather, I think the depression that is supposed to be cut into the slide stop isn't deep enough to arrest the plunger from protruding further than it's supposed to.

 

[Koda94]

Try this from the 1911 forum. Photo in post #405
https://forums.1911forum.com/showthread.php?t=214653&page=17

thats an option but I dont really like the idea of modifying something to fix a defect. I need to determine the cause first which is what Im trying to figure out. Ive never had this issue with any other 1911...

 

[Koda94]

I don't think the plunger is sticking out too far.

Rather, I think the depression that is supposed to be cut into the slide stop isn't deep enough to arrest the plunger from protruding further than it's supposed to.

I did some measuring with calipers and compared to another 1911 that works fine. I also swapped slide stops and the SA slide stop went into the other 1911 fine. The SA plunger protrudes .089", the other 1911 protrudes .069", to the problem gun protrudes .020" more... thats significant. (I still dont know what the nominal spec should be)

The plunger protrudes enough that the slide stop is side loading the plunger instead of contacting on the face of the spherical radius tip. I don't even know if the modification Don P suggested will help...

 

[Koda94]

Here are some pics of the problem child...

and yes, this has caused me an idiot scratch

 

[Jim Watson]

Looks like a lot of protrusion.
The straight section of the plunger is .222" plus the .045" tip radius. .267" from stop shoulder to tip.
Of course the internal plunger tube shoulder might be off, too.

 

[Koda94]

Looks like a lot of protrusion.
The straight section of the plunger is .222" plus the .045" tip radius. .267" from stop shoulder to tip.
Of course the internal plunger tube shoulder might be off, too.

thats what I'm thinking is the either the plunger or plunger tube is out of tolerance. It protrudes significantly and visually more than other 1911s.

I'm uncertain how hard it is to disassemble the thumb safety to remove and measure the plunger, or if its even ok to do that without affecting the fit or function of the safety. If its the plunger tube Id have to have a smith replace or send the gun off into shipping/warranty neverland for who know how long. The problem is unique enough Id also have to prove to Springfield their parts are out of tolerance and thats impossible without their prints...

I'm hoping this is something I can repair on my own, but if its the plunger tube I'm not certain I want to invest in any tooling to replace it if thats required...

 

[Jim Watson]

Getting the safety off to release the plunger assembly is a little fiddly but reasonably operator serviceable.
If the plunger is too long, it would not take long to reduce it with a drill and a file, keeping the hemispherical tip.
Or, groove the slide stop or use an implement

 

[Koda94]

Another factor may be the finish and galling of the stainless gun.... It also appears to be heavy MIM marks on the parts. A solution might just be finer finishing of the plunger and polish the surface of the slide stop.

I looked at the plunger on a 3rd 1911 today that, by eye, appears to protrude as much, but no issues assembling.

Outta time today for holiday events, but will measure that one tomorrow and compare side by side.

 

[Scorch]

Shorten it up enough that you can snap the slide stop back in place. I have done this to customers' guns a number of times.

 

[Koda94]

up late after holiday events tinkering with this into the evening...

I compared to yet another 1911, measured its plunger protrusion at .094"... which is more than the Springfield, so I can rule out that the Springfield protrudes way more than other 1911s.
I swapped slide stops. The other went in the SA just fine. The SA slide stop would not go into the other 1911, same issue. The other 1911 I mentioned above where it worked, the plunger does protrude about .020" less so that must be why it worked there.

So I compared slide stops with the one that the plunger protrudes about the same, big difference in geometry. The 1st surface that engages the plunger is super tiny on the SA slide stop.

So the problem is the slide stop... easy fix. I think I will buy a new one but for now I ground the surface larger to match the one that worked and it goes in better now. Not as smooth like the steel frame plunger but enough to make it operable in the field if needed there. Being a stainless gun, I was also able to sand out most of the idiot scratch so that none of it shows outside the slide stop... win win.

What a silly dilemma. Hers a pic, the stainless one is the bad one before I ground on it.