Make that three, I use a piece of old guitar string as a spring. I drill, and tap, a hole in the rear of the trigger plate, and a small hole in the lower rear of the trigger bar, and bend up a piece of fine music wire to lightly lift the trigger bar, and keep it from rattling, screwing it down at the rear of the trigger plate with a small screw.
I've fixed dozens of old kit guns for young shooters this way. Unless the lock is a very modern reproduction model, it will have two different positions for half cock, and full cock. Even the early Silers had this problem. Jim Chambers fixed this issue when he bought the company.
Hungry Horse