Use the detent tool https://www.printables.com/model/1150135-safety-detent-tool-for-ruger-pc-carbine-and-22 when removing the cross-pin or you will have to use it later to re-install the detent and spring (and there is a very real risk that you will never find the tiny parts again when they fly off, the spring has plenty of pressure…)
Uses M3x8 cylinder head hex screw from Prusa spares, the it doesn't bit at first use a drill bit to give a bit of cut to the plastic to get started.
The author marked this model as their own original creation.