this is an accessory for an air gun not a "real" gun

Supressor for pellet AIR riffle
Weihrauch
beeman 1336 1335 and similar models
thread is M12 x 1 and after print may require some cleaning.
print horizontally without supports
Fit 5.5 and 6.35mm versions.

Instructions for removing original beeman supressor:
remove front cap of supressor. It may be glued and you will need some force/heat.
remove internals chambers and coil
Remove 2 nuts and then supressor will slide of.
(See photo)