SCAR Muzzle/Barrel for Captain_Slug's Homemade Nerf Blaster Caliburn or any blaster that uses McMaster-Carr "5/8" Aluminium tubing as a barrel. Designed with several inputs from reddit user Thunderkrunk.
Modeled for a snug fit on ~16.1mm OD barrel. The barrel material has some tolerance.
I used .4 mm Fishing Line (picture) as to string the muzzle/barrel.