end 110 the springs 138 operably coupled with the tangs 116 are seated within a stepped portion 103 on the distal end 110 of the barrel body 102 the distal end 110 further includes at least two cutouts 112 that seat the at least two protrusions 143 of the distal engagement portion 141 of the inner shaft 140 in one embodiment the proximal end 108 of the barrel body 102 includes a threaded portion for fixedly associating the barrel body 102 to the handle 180 in one embodiment the distal end 110 of the barrel body 102 includes an opening 109 with a width w b that is greater than or equal to the width w t of the screw body member 122 such that the screw body member 122 coaxially fits within the opening 109 on the distal end 110 the barrel body 102 is generally cylindrical in shape however it may assume alternative cross sectional shapes such as circular elliptical square rectangular polygonal and the like as shown in fig7 the inner shaft 140 is coaxially coupled within the barrel body 102 whereby the proximal end 142 of the inner shaft 140 protrudes from the proximal end 108 of.