I was given this Glenfield 75C some years ago. It seemed to function fine but would not fire. You could cycle the bolt, chamber the round, pull the trigger and hear it hit the firing pin but no bang... No firing pin mark on the rim.
So I finally took it apart thinking the firing pin was broke but it's not. What I found is slop between the back lug of the receiver and the fire control group frame where they are connected by a .25" pin. The hole in the lug of the receiver is a bit larger (worn?) then the holes in the FCG frame so this causes the FCG to shift back when fired and the hammer barely touches the firing pin.
Anyone else seen this problem and know of a fix. I guess I could try shimming the hole in receiver lug, just thought if someone else has been down this road there's no sense in me trying to reinvent the wheel.
Here's a photo of the receiver and FCG.