First thing, Huge thank you to @UlrikKristof_1149321 making this gun, I just modified somethings because I got lazy and didn't want to run to homedepot. Anyways heres the specs I'm using and I also uploaded a STEP file if anyone wants to mess with it. 

Air inlet: 1/4 Inch Male Quick Connect 

Media Hose: 12mm

Nozzle: 0.18 inch Ceramic tip ( I added an O-ring to the end of tip) 

https://www.harborfreight.com/ceramic-nozzle-assortment-4-piece-70821.html

Air Compressor: 20 gallons (I'm running it at 100 PSI, not ideal but works for me )