I don't know, but I don't think the Leica canisters would work on a Bessa. They have a mechanism that a Leica is designed to open when inserted and I doubt the Bessa is built to do that. Generic plastic bulk load canisters available from most online camera stores work great though. They're cheaper on an individual basis, but not really meant to last forever like the Leica ones. You need to throw them out when the felt starts to breakdown or collect any dirt, otherwise you will get light leaks and/or scratches. Just inspect each cartridge prior to reloading.
Bulk loading can be a great option for saving money and lets you load as many or few frames as you want, but I eventually got away from it as it was too much work for me... I'd rather spend my time shooting or printing.