Abstract: A closing plug for receipt by a threaded flange that is assembled into a drum end includes an externally-threaded body for receipt by the threaded flange. A radial flange is arranged adjacent a first end of the threaded body and the radial flange has a modified hex shape, thereby providing six flange portions. An outer section of each flange portion is formed into an axially-protruding projection such that as the closing plug is advanced into the radial flange, the axially-protruding projections abut up against a portion of the drum end in order to limit the threaded advancement of the plug. The abutment of the axially-protruding projections occurs after the desired tightening torque on the plug as received by the threaded flange has been achieved.