1917 grooved hammer vs Registered Magnum hammer

[fungunnin]

From my understanding the only two hammers with concentric grooves on the flats were early 1917 hammers and RM hammers. I recently acquired a grooved hammer and I think it is an early 1917 hammer but hopefully someone here can tell me definitely of it is a 1917 hammer or a RM hammer. Here are a few pictures.
Thanks,
~Bill

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[LoboGunLeather]

I am happy that someone knew what I had, even if I had no clue! Best regards! Glad it found a good home.

 

[handejector]

1917 Hammer.

 

[NavySCPO]

Okay now that’s over, wash your feet and put some shoes on.

By your casual attire one might assume we were all just lounging around doing nothing , hanging out in pajamas and bare feet.

Oh wait...never mind...

 

[Hondo44]

See this thread Post #16 to know how to tell the difference from the checkering on the hammer spur: Humpbacks in Magnums

Also there's two grooved hammers for the 357 mag, standard and optiononal Hump Back; both shown in the above thread.