If you can tie your boots then you can install a Jewell in a M70......it's easy. Being you don't have any bolt release to deal with it is a matter of pounding out a couple of pins, sliding the trigger in and knocking the pins back in. At least that is what I remember of it anyway.
Just don't let the barreled action slide down the table and hit the floor, triggers don't like that, I know a guy who did this once.
and no it wasn't me.