Due to the nature of the mechanical design, in my experience, most pre-64 Model 70s are pretty stiff to place in on. They don't just block the trigger, they block or interrupt the firing pin.
The bolt, bolt shroud and safety of these rifles are not very hard to take apart and put back together. I would suggest that you get a good set of instructions, dismantle and clean very thoroughly, lighty lubricate, re-assemble and test it before you think of doing anything else. It will still be somewhat stiff to operate, but it should be smooth, not gritty.
Hope this helps.
Mannyrock