Quote Originally Posted by Uncle Goose View Post
I would strongly go against using 120 in a 220 back, the pressure plate is different in the 220 as it has no backing paper. Use the appropriate back for the 120 film, it's not gonna break your bank.
The preasure plates are exactly the same in a 120 and a 220 back, with a spring loaded plate adjusted to 0.75mm-1mm clearance to the film mask.

The real difference between the two is in the frame counter n frame meter disk. The wind has to compensate the wind length of film with no paper backing. But if you start the leader at one turn on the take up spool, it will align the frames on your film strip and give you the proper amnt of pictures although the spacing may be different but not overlaped and get wider as you go to the end of the strip.

BTW... inserts are not all created equal. If you swap inserts you are asking for light leaks n latch problems. The seating is different amongst the various models.