Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2885176.
This fake suppressor/ silencer was designed for the KWA Mk23 but it should fit other guns with a 16mm+ (CW) thread aswell. It's about 18.5cm long and has a diameter of around 3.4~3.5cm.
Disclaimer: I am not giving exact numbers as i had to upscale my print to around 104%. If you've a good printer that's well set up and calibrated you may not have to do so. I still advise to do a test print of the outer shell in which you just stop and test fit when the print reaches a height of around 1 cm.
Assembly: You need 1 outer shell, one endcap and 7 baffles. Put the baffles inside the tube of the outer shell with the narrow side facing the threaded part of the outer shell (As seen on the 2nd photo). Use a stick or a long screwdriver to align the baffles for a straight fit. To finish it get a hot glue gun and simply glue the endcap to the outer shell.