Abstract: An apparatus for mounting a scope on a rifle without the necessity of drilling or tapping any holes in the rifle receiver. A small removable plate has a configuration which permits it to be inserted into a prepared recess along the side of the rifle. The plate has front and rear edges which are appropriately shaped and sized so as to be inserted into confronting grooves which coincide generally with the front and rear boundaries of the prepared recess. The plate is configured so as to abut a rigid portion of the rifle (e.g., a top portion of the receiver) in order that there will be a limitation on its upward movement. The plate has threads which are accessible from the outer surface of the plate; preferably, these threads are female threads in a central bore which extends through the plate. A base for holding a scope is selectively mountable on the plate, so that the scope will be essentially parallel to the bore of the rifle.