Since the Model 60 trigger is attached to the trigger guard, and uses lever action to work the sear in the lower receiver, it sounds like an alignment problem. You might try putting a washer or two between the trigger guard (over the rear screw) and the stock wood - prevent it from going in too deep.
Also, is your trigger return spring still in place?
My Model 99M1 (based on Model 60 action) is missing the spring, but trigger still functiions okay.
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