A silencer for an Airsoft M4 / AR15, it is 34x120mm in size, has a 14mm thread to screw it to the outer barrel. The tube and the end caps have a 32mm thread. The spring is from another aluminum silencer, the foam has an outer diameter of 30mm. I cut the foam to length with the cutting template and punched out the holes with the cutter template. The foam with the different hole sizes makes the silencer quieter.

Foam: https://lmy.de/jfXtO

Update: Added cutting template and cutter template.