Abstract: A mount for securing a gunsight to the top of a revolver. The mount is secured to the sideplate of the revolver by at least one screw which passes laterally therethrough. Two existing sideplate screws are removed and replaced by specially configured auxiliary screws threadably received in existing tapped holes in the revolver frame. The mounting device includes a first portion adjacent the side plate of the revolver, a second portion extending vertically upward along the rear frame portion of the revolver and a third horizontally projecting upper portion that receives the gunsight. The horizontally projecting upper portion is fitted with two inwardly projecting opposing rails aligned at a diagonal angle relative to a true vertical. The inwardly projecting rails provide repeated accurate securing of the mount to the firearm.