The 15-22 (like the 15-1/Improved Family) uses a long beak shuttle, which is a different mechanism to the ones on the later 15s. It's interesting because they (being the 15-1 and 15-22) are mostly identical to later models, bar the bobbin mechanism. I'm a huge fan of mine; it's a beautiful machine to use, though it's honestly louder than other 15s I've used, which is likely down to that bobbin mechanism.
It's a fantastic machine, and it's definitely an experience working with a machine that's more than 5 times my age
