Howdy
the top inside edge of the MSH has to be radiused so that your sear spring has some travel. The sear spring is not holding pressure on the sear-to-hammer engagement surface, thus no halfcock and the light pull. If you compare the MSH's you will see that the stock Detonics is rounded on the top inside edge. What was the reason for replacing the MSH?
L8r
Conley Janssen