This grip is for a .25 ACP revolver of "Velo Dog" type made just after the turn of the century by an unknown maker. It has a dog's head trademark.
Dimensions / Sizes for the Velo Dog .25 Revolver Dog Logo w/Hammer
Measuring right panel from backside (vertical not diagonal)
1 3/4" long
7/8" wide across center of screw hole
27/32" wide across center of pin hole @ butt