I just got a satin blued 2" Round Butt M&P serial number 833915(no S stamped before serial number on butt).There IS a S stamp on the left side grip frame under the Stocks,on the Yoke,Barrel flat,cylinder face under ejector star and on the bottom of the ejector star itself.Now for the intersting part....The Gun has the old style pre war style hammer block(confirmed be removing the side plate),NOT the newer sliding safety block.Why would they stamp all of those S stamps and then use the pre war Hammer safety?

without pictures it doesn't really exist. You know that!

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Randy
Provenance nerd

It is an early post war revolver. I once encountered the same thing on a 2" M&P in the past that shipped in 1946 if I recall. I learned the S is still part of the serial number, there was no room for it on the butt, so it was stamped on the side per Mr. Jinks.

The S does not refer to the safety.

By the serial # it's a pre 1942 production likely made in the late 1930s.

The S most likely stands for the Service Dept.

Since you didn't state that there's a star on the butt or a rework date on the left side of the grip frame, the S is an indication the gun went to the service dept before it was shipped as a new gun.

This is done when a completed gun needs rebluing or some other correction work before being shipped new.

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Jim
S&WCA #819

My research shows it was to denote the new sliding Hammer Safety.There are other Guns from the same era with the S stampings all over the place that do have the sliding safety.This One is an anomaly it seems.If the S was just on the grip frame I could see your theory but it being all over the place is something different.There is no S on the Butt of the Gun in front of the Serial Number as there was not enough room.Another Member with a Gun about 25 serial numbers away Lettered his without the S and it came back as a completely different Gun.He then lettered it with the S and it came back as a 2" M&P that was One of the First 100 shipped after the War.

ETA:there are no rework stampings or Dates.

In which direction of the muzzle does the serial number on the grip frame read?

Muzzle right - prewar, may not have been shipped until after the war
Muzzle left - postwar

Do all the parts have matching numbers and the S?

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Alan
SWCA LM 2023, SWHF 220

Muzzle left,All parts have the matching serial number and the S.Here is a link with the Gun just like mine in post #13.

Post-war Pre-war 2" M&P

When you say just like ours: Does it have a post war sliding bar safety?
S in all 5 serial # locations except the butt?
One line address?

Yours could very well have "shipped" after the war as well. My original post indicated its production period not it's shipped date.

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Jim
S&WCA #819

Need some pix. That "S" you mention, if NOT on the butt inline with the serial number but UNDER the grips on the grip frame .... the S could just stand for "STANDARD" (BLUE) finish. That serial number would be pre-war and possibly in one the lend-lease, Pre USA entry to WWII, serial number ranges.

Post some pix, please.

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ANTIQUESMITHS
LM1300 SWHF425

It has the one line address,The owner of the Gun in the link has since sold it so I can't speak for the markings on it.I am sure the Gun shipped post War,Probably in 1946.

Post war safety?

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Jim
S&WCA #819

Sort of confusing. If it does not have the improved 1945 hammer blocking safety, it would necessarily have been built on an earlier (probably pre-WWII) frame. If so, I have no idea why there would be an S prefix to any of the serial numbers.

Yeah it really is. But he didn't say the S was a serial # prefix:

"There IS a[n] S stamp on the left side grip frame under the Stocks, on the Yoke, Barrel flat, cylinder face under ejector star, and on the bottom of the ejector star itself."

That's why I thought S for Svc Dept. If it is a prefix, that's a horse of another color.

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Jim
S&WCA #819