How did I miss this?

[SimmerinLightning]

Sitting here fiddling with my MWnN conversion/not a conversion, and I see a screw into the side of the hammer which I somehow never had noticed before. Closer inspection reveals a crescent-shaped toggle in the front face of the hammer just below the firing pin. Manipulation with a toothpick or similar causes it to flip over, the reverse side being convex, preventing the hammer from dropping the last fraction of an inch and impacting the primer. It can easily be disengaged with a finger.

Do other modern conversions have this? Did period conversions? Its practical usefulness seems limited to anyone who actually might have carried a revolver for defensive or nefarious purposes.

[SimmerinLightning]

It appears I found my answer here:
http://www.gunblast.com/Cimarron_Conversion.htm

The Cimarron Richards-Mason .44 is a faithful reproduction of the original, with the addition of a hammer-block safety to allow the legal importation of the sixgun.

[Coffinmaker]

Yep.  Pretty much found your answer.  That little Hammer block was added to the gun to pass the BATF drop test requirement for importation.  It serves no other purpose.  Except to flip out at the most inopertune time and cause a miss-fire.  Suggest you take it apart (there are little parts in there) and liberally coat the pivot screw and the little wedge thingy with RED LocTite and let it set.  Your actually don't want it to ever move again.  Not even wiggle. 
Don't ask me how I know this

Coffinmaker

[Major 2]

another fine idea from the minds of the BATF think tank folks ....
first time it happens, you'll stand the with dumb on you face, ditto on  "Don't ask me how I know" 

The best safety is the one between our ears... sadly big Brother knows we must be protected from ourselves....

[HolliferADollar]

I call devices like that "lawyer pleasers".  They were in the hammers of my Uberti 1872s, but now are safely ensconced in the parts bin.

Holler