Google is your friend. I got the answer to my question.

What year is your rifle?

My understanding is that early vintage rifles had a factory adjustable trigger and could be worked to a very nice break. At some point though, the trigger was changed and while the screws are still there, adjustability is practically ineffective. I don't know when this transition occurred.

I've been steadily changing over to Jard triggers any time I start messing with my rifles and want a better trigger break.

The early trigger had 3 screws, the 3rd being sear engagement.
Had to remove the buttstock to access it.

My 74 B in .22 250 has one.

However, with that linkage, after adjustment my
trigger is better but the safety is stiffer.

Best I can tell, my rifle is a 79 model, red pad. I had never really noticed the adjustment screw before today. I thought maybe it was after market but after a Google search I found out is a factory trigger. With my trigger pull gauge it breaks consistently at 2 pounds. A nice clean trigger for a hunting rifle.

These are pictures of a Moyer trigger. It is just a copy of the 3 screw Ruger trigger. These pictures may give you a better idea as the what the guts of a No. 1 really look like.




The original 3 screw looked like this. Not too many rifles were made with this trigger.

I have a 3 screw trigger siting in a box. Does anyone know it it will work in a newer rifle?
Fit on Moyers years ago, not sure if I received a out of spec unit, it was a lot of work getting it to fit and work.