Groovy!!! I'm really glad that it worked for you too. I was also very frustrated by this.
In retrospect, I wonder if the Soviet films that this camera was originially designed for had slightly different sized/shaped canisters which fit better. I have noticed that some canisters I use are hard to set into place.
Max Power, he's the man who's name you'd love to touch! But you mustn't touch! His name sounds good in your ear, but when you say it, you mustn't fear! 'Cause his name can be said by anyone!
Voigtlander Bessa R3A
CV 50/1.5 Nokton, J-12, J-8, J-9