They appear very similar dimensionally but no identical. The 659 hammer appears to have a half-cock notch and a few other slight variations. Will it function in a 6906? I really want a spurr. Thanks

It will function. It will not be very smooth. That half cock notch causes much of the grittiness. Far and away the smoothest hammers are the late MIM hammers. I DO have a hammer I bought as a spare that has the half cock notch ground off. It is VERY smooth. It seems to function fine, but I would not suggest that. I have smoothed down the front lower, rounded part of the hammer on a 3rd generation Smith, and that helped a great deal. The factory had some VERY rough finishes on some of those hammers.

The hammer strut is shorter on the 6906, you’ll have to swap it out.

Thanks for the feedback. Is the grittiness in double action only or also in single action? Would I just be better off finding a 5906 hammer?

Double action only.

Probably, especially if it was MIM.

John

I presume that you are trying to put a spur hammer on a 6906. The MIM parts tend to have smoother and more uniform surfaces, eliminating much of the grittiness associated with S&W's metal receiver pistols. I think you would be much happier with a MIM hammer, just remember to replace the 59xx hammer strut with the shorter 39xx/69xx strut.

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I did not notice the grittiness in single action, only on that long double action pull. You can smooth up those gritty hammers, with light application of 400 grit sandpaper and a buffing wheel. There has been a bit of a debate on here if that harmed any type of surface hardening on those hammers. I defer to any real gunsmiths on here.

Sooooo much better. The SA trigger pull is pretty gritty now however, that’s next on my list.