The photo shows the stock of a SIG M7 automatic rifle with a failed mounting unit. The standard M1913 clamping bolt was reported to have disengaged after the operator fell. According to the technical manual, this bolt should be torqued to 100 in-lbs (about 11.3 Nm). Currently two weak points have been identified in this stock assembly: the tube mounting screw and the M1913 clamping screw. On the one hand, this can be considered a positive factor in terms of durability: the presence of such "weak links" helps prevent damage to the lower shelter in case of emergency situations. However, dropping or "knocking" a jammed cartridge case by striking the butt against the ground (the so-called "mart" method) is entirely within standard operating conditions.

The photo shows the stock of a SIG M7 automatic rifle with a failed mounting unit. The standard M1913 clamping bolt was reported to have disengaged after the operator fell. According to the technical manual, this bolt should be torqued to 100 in-lbs (about 11.3 Nm). Currently two weak points have been identified in this stock assembly: the tube mounting screw and the M1913 clamping screw. On the one hand, this can be considered a positive factor in terms of durability: the presence of such "weak links" helps prevent damage to the lower shelter in case of emergency situations. However, dropping or "knocking" a jammed cartridge case by striking the butt against the ground (the so-called "mart" method) is entirely within standard operating conditions.