Johnson Bye & Co. of Worcester, Mass. (the predecessor of Iver Johnson) produced this .32 caliber solid frame single action revolver circa 1880.
Dimensions for the Iver Johnson .22 Break Top Revolver
Measuring right panel (vertical not diagonal)
2 9/32” long
1 1/32” wide across center of screw hole
31/32” wide across center of pin hole @ butt