An adjustable mounting system for a telescopic scope includes an adjustable elevation mount formed from a scope ring and an adjustable sub-base. A clevis portion of the scope ring holds an elevation pin that is received by a vertical slot in the adjustable sub-base. An internally longitudinal bore is disposed though the adjustable sub-base and an externally threaded barrel disposed in an opening of the longitudinal bore. A cylindrical elevation cam having an angled slot is disposed in the longitudinal bore and includes a positioning rod that extends through a bore disposed through the barrel. The angled slot receives the elevation pin as it extends through the vertical slot of the adjustable sub-base. The positioning rod has a shoulder portion that receives a set of roller thrust bearings and has a threaded distal end. An internally threaded dial thimble extends over the positioning rod distal end and shoulder portion to engage the external threads of the barrel. A thimble locking nut engages the threaded distal end of the positioning rod so as to affix the dial thimble to the positioning rod. Bi-directional longitudinal travel of the elevation cam is accomplished by rotation of the dial thimble.