New marauder 22 caliber Lothar Walther barrel

Csbrown,
You need to drive 49 miles North! Every airgun question and more answered face to face, and, you'll get to shoot a lot of different airguns as well as meeting all the people in your area.

?? That barrel should be a custom shop part(?) if so in theory the only way tom get one is to0 have a custom shop rig - and serial number- then you could buy parts from the custom shop[. Or maybe they have changed?

You did catch that your regulator is the Altros from Lithuania right? ( and some folks at the GOB know that reg) Top of this page:
https://avveduti.wordpress.com/2010/07/10/marauder-project-installing-a-regulator/
gives some info, which way to turn for pressure adjustment.

http://www.gobft.net/
http://www.invictaftc.org/

John