During some recent practice to further break-in St. Paddy’s Rifle, a troubling incident occurred. After about 15 rounds downrange, I fired fired a round and very, very slowly released the trigger. The rifle discharged!
I fired another round and released the trigger quickly. The only sound was a click as the disconnector caught the hammer and held it so the trigger could reset for the next shot. OK, so I unloaded the rifle and removed the upper receiver. Controlling the hammer with my thumb, I ran the fire control group through a safety check several times. Whenever I released the trigger very slowly after resetting the hammer, the hammer would fall. Clearly it was a case of early disconnector timing.
Here is the disconnector just removed from the lower receiver.
To allow the disconnector more forward movement to ensure hammer capture during trigger reset, I stoned the underside of the nose where it stops against the trigger. With the rifle reassembled, I tested the disconnector fifty times. Now the trigger functioned perfectly.