Hi-
Anyone have detailed pictures/instructions of the firing pin and bushing in the 640 no dash centennial? The one that is held in place with an external pin through the frame, and I believe has to be removed out of the front of the recoil shield/breech face.
Thanks

There are schematics of the model 640, and the 43 on the Numrich web site showing the configuration of the parts.

640 S&W Accessories | Numrich Gun Parts


43 S&W Accessories | Numrich Gun Parts

__________________
Ret. LE, FA Instr, S&W Armorer

It's done just like the rimfires (17, 617 etc) with the external cross pin.

Remove the cross pin. Use a drift to push the firing pin (and firing pin spring and bushing), towards the barrel.

The bushing is drilled in place, like front sight blades, so when re-installing you have to carefully align the bushing before pushing it (and the firing pin and spring) back into place.

Thanks for the info.
Any issues with dry firing this type of FP and bushing? The reason I ask is that after dry firing the busing on mine moves out a bit, just a hair. When firing live ammo it stays flush.

Although the warning about dry firing from S&W includes only rimfire guns, I personally don't dry fire any revolvers in which the firing pin is frame mounted.

__________________
Ret. LE, FA Instr, S&W Armorer

armorer951 thanks for the fast response. I am not going to dry fire this one any more. Do you see any issue with slight movement of the bushing I described?

Probably peening on the cutaway at the top of the body of the bushing that accomodates the crosspin. (securing the bushing) If the movement is very slight it's not a problem. If the bushing protrudes past the breechface surface too far it could interfere with cylinder rotation, by catching on the case rim, or interfering with proper headspace. I would keep an eye on it for sure. Is this your carry gun?

__________________
Ret. LE, FA Instr, S&W Armorer

Thanks again, I will keep my eye on it. It is my carry gun.