There is no ridge where the green narrow is pointing but the is where the blue arrow is pointing.

I'm guessing someone did some machining there. Any idea why someone might do that??

__________________
Kenny
Endeavor to persevere.

The area of the recoil shield near the hammer nose bushing (blue arrows) stands out further than the green arrow area and contains all the force of firing, so would show a deeper indentation in the metal.

The green arrow points to a mark made by a (presumably loaded) round backing up and hitting that area with firing. There is a similar mark at the 6 o'clock position. These marks are commonly seen in guns with higher round counts in my observations.

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Alan
SWCA LM 2023, SWHF 220

I’d say it left the factory like that. I’m referring to the surface variations in the recoil shield, not the case head imprints caused by recoil after substantial firing.

I just looked at an old K-38 Masterpiece that I had in my range bag. It has the same arched ridges on either side of the hammer nose bushing (blue arrows), although not quite as deep as your friends .357.

Mine does not have the surface variation that you pointed to with the green arrow. I suspect it’s simply the result of factory polishing of the recoil shield, where the worker held the frame at a slightly different angle when polishing the top of the shield. These older guns had a lot of skilled handwork and some variation is to be expected. The finish also looks unmolested.

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"I also cook."

Thank you very much for your help.
I was worried that an amateur gunsmith had gotten ahold of it.

__________________
Kenny
Endeavor to persevere.