A rotary-percussive hydraulic perforator comprising: - a body , - a shank mounted in the body and intended to be coupled to at least one drill bar equipped with a tool, - a striking piston slidably mounted inside the body according to a striking axis (A) and configured to strike the shank , the striking piston including a braking surface which extends transversely to the striking axis (A), - a braking chamber configured to hydraulically brake the striking piston when the striking piston exceeds a predetermined striking position, the braking chamber being configured to be partially closed by the braking surface of the striking piston when the striking piston exceeds the predetermined striking position, characterized in that the rotary-percussive hydraulic perforator further comprises: - a stop piston which is tubular and which is slidably mounted inside the body and around the striking piston along an axis of displacement substantially parallel to the striking axis (A), the stop piston being configured to apply a pushing force on the shank , the stop piston comprising a bearing surface configured to abut against a stop surface provided on the body , so as to limit the stroke of displacement of the stop piston towards the shank , and in that the rotary-percussive hydraulic perforator is configured such that the bearing surface and the stop surface are axially spaced apart from each other by a predetermined spacing distance (D) simultaneously when: - the shank bears on the stop piston and is in contact with the striking piston , and - the braking surface of the striking piston is located at an inlet edge (15.1) of the braking chamber . - a body , - a shank mounted in the body and intended to be coupled to at least one drill bar equipped with a tool, - a striking piston slidably mounted inside the body according to a striking axis (A) and configured to strike the shank , the striking piston including a braking surface which extends transversely to the striking axis (A), - a braking chamber configured to hydraulically brake the striking piston when the striking piston exceeds a predetermined striking position, the braking chamber being configured to be partially closed by the braking surface of the striking piston when the striking piston exceeds the predetermined striking position, characterized in that the rotary-percussive hydraulic perforator further comprises: - a stop piston which is tubular and which is slidably mounted inside the body and around the striking piston along an axis of displacement substantially parallel to the striking axis (A), the stop piston being configured to apply a pushing force on the shank , the stop piston comprising a bearing surface configured to abut against a stop surface provided on the body , so as to limit the stroke of displacement of the stop piston towards the shank , - a stop piston which is tubular and which is slidably mounted inside the body and around the striking piston along an axis of displacement substantially parallel to the striking axis (A), the stop piston being configured to apply a pushing force on the shank , the stop piston comprising a bearing surface configured to abut against a stop surface provided on the body , so as to limit the stroke of displacement of the stop piston towards the shank , and in that the rotary-percussive hydraulic perforator is configured such that the bearing surface and the stop surface are axially spaced apart from each other by a predetermined spacing distance (D) simultaneously when: - the shank bears on the stop piston and is in contact with the striking piston , and - the braking surface of the striking piston is located at an inlet edge (15.1) of the braking chamber . - the shank bears on the stop piston and is in contact with the striking piston , and - the braking surface of the striking piston is located at an inlet edge (15.1) of the braking chamber . <EOS>