at the crook the upper end 57 of tang portion 56 has a transverse bore for pivotally supporting lever 58 it is noted that the upper reach of portion 57 is surrounded on all sides by the framework of lever 58 due to the proximity of the transverse members 58b and 58c the freedom of motion of lever 58 about portion 57 is limited in this view eccentric 61 is shown rotated 90 u00b0 in comparison to the position shown in fig7 accordingly the eccentric bears upon the rearmost end of tang 56 thereby holding it against the wall of receiver 14 under these circumstances trigger 50 including its tang section 56 cannot move therefore the striking face of hammer head 60a remains lodged in notch 18g although bolt carrier 18 is urged forward by compression spring 16 fig7 the connection between hammer head 60a and notch 18g prevents any movement to facilitate an understanding of the principles associated with the foregoing apparatus its operation will now be brief described to allow firing of the weapon eccentric 61 is rotated 90 u00b0 to the position shown in fig8 b it will be noticed the coil of spring 62 is translationally fixed at the pivot of hammer 60 and urges lever 58 and hammer 60.