On a GP or SP-series Ruger revolver, the forward lockup happens on the yoke. This bolt will go into a recess in the frame, to secure the cylinder.
Kimber K6S 2
Re-Inventing the Wheel
On a GP or SP-series Ruger revolver, the forward lockup happens on the yoke. This bolt will go into a recess in the frame, to secure the cylinder.