Internal Rust issues - S&W Model 40

[Moo Moo]

Hi all

I picked up this S&W Model 40 a little while ago. It's serial number is 15617. I'm not sure on its age apart from the 5th Ed Standard Catalog of S&W saying 1952 to 1971 (1 to 30160 - Page 584). Anyway, Iast weekend, I finally had a chance to open up the side plate and have a look inside. As you can see, there's a bit of rust on a couple of the internal parts. Other than the 0000 steel or bronze wool and some oil, is there any other suggestions on how I go about cleaning the rust of these parts? There is also some gold paint, and touches of red, on the front sight. How best would I go about trying to remove this without wrecking the bluing underneath it?

Thanks
Moo Moo

 

[Retired W4]

That M-40 will require a complete disassembly for restoration but I know you understand that. Besides that I noticed the sliding hammer block and the pin in the trigger return slide that the hammer block rides on are missing. I'm not that familiar with that model but I'm pretty sure those parts should be there. Acetone will remove the paint without damaging the blue. I would buff the rust with oil and 0000 steel wool as you mentioned. The cylinder bolt, DA lever, hammer spring guide, etc. should clean up well. Be careful with the case colors on the trigger. Surface corrosion on the exterior should clean up with judicial use of Simichrome.

One feature of the M-40 has to do with those pin holes on the grip frame. S&W put a pin in one that can be moved to the hole in the grip safety to hold the safety down, defeating the safety. I always thought it strange that S&W would do that. Good luck with it.

Edit to add: after disassembly I like to soak all parts in a solvent like Hope's #9 for several hours before buffing. Have fun getting the hammer spring back on the guide.

 

[Muley Gil]

That M-40 will require a complete disassembly for restoration but I know you understand that. Besides that I noticed the sliding hammer block and the pin in the trigger return slide that the hammer block rides on are missing. I'm not that familiar with that model but I'm pretty sure those parts should be there. Acetone will remove the paint without damaging the blue. I would buff the rust with oil and 0000 steel wool as you mentioned. The cylinder bolt, DA lever, hammer spring guide, etc. should clean up well. Be careful with the case colors on the trigger. Surface corrosion on the exterior should clean up with judicial use of Simichrome.

One feature of the M-40 has to do with those pin holes on the grip frame. S&W put a pin in one that can be moved to the hole in the grip safety to hold the safety down, defeating the safety. I always thought it strange that S&W would do that. Good luck with it.

Edit to add: after disassembly I like to soak all parts in a solvent like Hope's #9 for several hours before buffing. Have fun getting the hammer spring back on the guide.

There is no need for those parts, as the hammer cannot be struck externally.

 

[Tom S.]

Looks like a glovebox or tackle box gun. All the parts appear salvageable, though removing the rust on exposed parts like the release latch screw will require re-bluing, at least with a cold blue product. Flat parts might respond well to judicious use of a fine file. Round parts can be put in a drill chuck. Some oils contain rust inhibitors while others do not. I'm not a big proponent of Amsoil, but they do use rust inhibitors in some of their products - look for it on the label.

For the sight, I would try fingernail polish remover (acetone) in a small spot and see how it works. You might also be able to remove the paint with a copper wire brush.

What, if anything, you decide to do with the exterior is up to you. Re-bluing or plating will probably run around $200 - $300. A do-it-yourself finish like parkerizing or Cerakote is also an option, and the latter will help hide minor blemishes.

 

[Retired W4]

There is no need for those parts, as the hammer cannot be struck externally.

S&W and a common sense approach. Thank you.