The "Young America" is a solid frame double action revolver made by Harrington & Richardson from the mid-1880's until WWII. During that time about one and a half million were produced.
Dimensions / Sizes for the H&R Young American .22 Revolver;
Measuring right panel (vertical not diagonal)
1 15/16" long x1" at widest point
15/16" from center of screw hole to butt
Grips #3645G ($41.50), Screw Kit #7270 ($16.00)