"Filing-to-fit" of certain parts during production limited interchangeability. The exposed rear sight had no protective ears and was vulnerable to breakage. The adjustable front sight could be lost if the retaining screw wasn't tightly secured. The weapon was susceptible to jamming if grime clogged the bolt's locking recess in the receiver. The two small magazine guide retaining pins and corresponding receiver stud holes were tapered allowing disassembly and assembly only from one direction—right to left for disassembly, and left to right for assembly; adding unacceptable levels of complexity in a combat environment. The retaining pins had to be delicately tapped out whenever the bolt needed to be removed for cleaning; again, an awkwardly involved task whilst under fire. And afterwards when the pins had to be put back during the reassembly process, if they were inserted either too far or not far enough, the receiver might not fit back into the tight confines of the stock.