Due to some overhangs do not exeed 0.2 mm layer height with 0.4 mm nozzle. With that layer height and nozzle the printing does not require any supports.

For the muzzle break to ‘lock’ in place use a 6 mm airsoft pellet and place it in the hole under the model. Seen in one of the pictures.

The part in the images was printed using Prusament PETG Matte Black.