Well, I got to the range this afternoon to test the 'fix'.
What a surprise. Instead of shooting 2 1/2" all over the place, I'm down to about an inch, just what is advertised. The load is the same, only a .376" oversize hinge pin. Now I'm going to do some load development and I'm thinking of having the trigger re-worked. It's a bit sloppy and rough compared with the Shilen competition on my Rem 700 SingleShot. I'm sure that the groups would be smaller with a better trigger.