A Tale of Two Brothers

[dobegrant]

Congratulations you have a really nice pair of revolvers there

 

[TheTinMan]

Colt called it a "Fouling Relief". It was a feature on every Colt revolver from black powder times until now.

I had never noticed the “fouling cup” on my Colt 1917. The photo above is the S&W. There is a similar cutout on the Colt, but it is farther forward and nearly centered over the end of the forcing cone.