HELP WITH INSTALLING A DOUBLE ACTION SEAR IN A S&W 646

[KEVCON]

HELP!!!!!

I have installed double action sears in 617's, 629's and 686's. However, when I took the side plate off of my Smith & Wesson 646 the internal action doesn't look like the series of firearms I just listed above. Normally there is just the sear and spring. For the 646 there appears to be a sear, spring and a pin (see picture below).

I have no clue how to reassemble this S&W 646 and would appreciate help.

I have searched the internet and I could not find a schematic or instruction that would help.

Does anyone have specific instructions and/or diagrams that I can use to reassemble my S&W 646 so that it functions correctly?

Thank you!

 

[Kernel Crittenden]

I have one of those in my little parts box, here. But I'll be gosh darned, because I can't remember what it does or where it goes. I'm not even 100% sure it goes to a Smith.

 

[colt_saa]

Your 646 is a 100% normal action for a forged hammer.

I am betting that the 3 other you have done were relatively modern S&Ws equipped with a MIM hammer. The newer design reduces the use of tools