A builder said an SMP5K22 charging handle was too tight after first assembly, and an M3 fastener in the handle bent while trying to cycle the action. An M4 fastener was used in its place.

After another maker shared an anti-rotation approach, the builder made a personal version that has not been printed and is marked beta. It specifies a cap-head M4 screw and may need a slightly larger hole in the charging tube, depending on the hardware.