Last week a new 10/22 owner asked about his failure to fire problem with the following symptoms: “Removed trigger guard today for cleaning. Reinstalled. Hammer won’t fall and safety has lost its detent feeling. Removed trigger [group] and out of gun it is still cocked and won’t release.”
What happened is that while holding the safety in the centered position to remove the stock, the owner rotated the safety slightly so that the cutout for the sear was no longer on top. There was no place for the sear’s front leg to descend so it could not release from the hammer. To explain how this happened, here are some pictures from The 10/22 Companion that show how the safety works.
Above is the safety. The safety is made from round bar stock with the cutouts machined in a CNC mill. At the left you can see the wide, flat cutout that is on top when the safety is installed. At the right, there is a scalloped cutout with two slots that is at the bottom. The safety plunger stands below the safety in a hole at the bottom of the trigger group housing and is pressed up against the safety by its spring.
The left photo shows the safety in the FIRE position. Inside the circle you can see that the entire flat cutout is under the sear’s front leg, providing a space for the sear to descend. In the right photo, the safety is in the SAFE position. You can see that the round barrel of the safety is now halfway under the sear, blocking it.
It’s possible to rotate the safety so that the top cutout faces to the side, which puts the cylindrical barrel of the safety on top for its full width – leaving the sear with no place to go. It isn’t easy to rotate the safety while it is fully on or off, because the plunger is captured in one of the bottom slots. But if you hold the safety centered, the plunger is riding on the point between the two slots, and the safety can turn easily.
To fix this, shine a light from the top of the trigger group to see if the flat cutout is facing forward (toward the muzzle) or rearward. Push the safety to the FIRE position. Grasp the ends of the safety and rotate it to put the cutout back on top. You should hear the detent click back into its slot.
To prevent this condition, always de-cock the hammer (by dry firing) before centering the safety for stock removal. If the hammer is cocked, the safety will not stay centered without holding it. But in the fired position you can push the safety to the centered position and it will stay there without having to hold it in place.