You are right Warren. Each barrel frame combination is different. My first Contender was a 14" 35 Remington. It was difficult to open or close the action.
It also mis-fired about one third of the time (that's too much).
I still have the frame and it works fine with others barrels.

Thinking back maybe my first was a 30-30 Winchester. It's late and I'm old and tired so all bets are off.