Thanks! You’re very lucky to be able to buy these parts. :-)

Hello, context would be great :-) What is that gun?

The Hitchhiker is a .22LR single shot without a magazine, and your’s doesn’t appear to be a Hitchhiker.

Unfortunately, it appears that the design is only available in imperial measurements.

It is also only available for barrel liners and not the quasi standard 16mm diameter barrels.

Look for Not-A-Chiappa or CLB on the Odd Sea for 22LR single shot designs.