Not listed in Iowegian's excellent tuning guide or the First Kuhnhausen double action manual is a severe inhibiting factor to consider before you begin an action tuning on any SP 101. It is not mysterious or difficult to fix, and you don't have to send yours back to the factory.
Remove the grips and observe the lower tip of the main spring strut to see if the lower tip is touching or riding over the frame casting as you reach the end of the cocking sequence. The strut is a stamped part....cannot be the wrong length, and deserving of careful deburring and polishing. The strut touches the frame casting on two of my three early .327s do this and it must be corrected or you will not succeed with any action job. You can follow all of the instructions and polish all of the articulating surfaces, but you will still experience gritty, late cocking stroke "stack" that will be present with all spring weights. All the dry firing and shim installation in the world will not correct this fault.
Don't ask me how I know this....thought I would share. I would like to know who else has seen this fault.
Just grind out or file the frame until there is no touching of these parts. Deburr and polish the the lower mainspring keeper while you are down there.
Remove the grips and observe the lower tip of the main spring strut to see if the lower tip is touching or riding over the frame casting as you reach the end of the cocking sequence. The strut is a stamped part....cannot be the wrong length, and deserving of careful deburring and polishing. The strut touches the frame casting on two of my three early .327s do this and it must be corrected or you will not succeed with any action job. You can follow all of the instructions and polish all of the articulating surfaces, but you will still experience gritty, late cocking stroke "stack" that will be present with all spring weights. All the dry firing and shim installation in the world will not correct this fault.
Don't ask me how I know this....thought I would share. I would like to know who else has seen this fault.
Just grind out or file the frame until there is no touching of these parts. Deburr and polish the the lower mainspring keeper while you are down there.
