Very common to have just a slight misconnection or angling of the hose on the barb will cause leakage. Samew it the sealing o-rings and threading for the cylinder. Everything should be by hand. Do make sure to read up on the maintenance of the trigger gun. You may not use water, but air containing moisture is the same as water. Learn how to strip it down and perform maintenance. Keep all moving parts lubricated accordingly. Since I also dabble in metalurgical materials as past time hobbies, make sure to coat the metal surface with either food grade mineral oil or silicone oil. They're cheap, and they will prevent rusts and pitting. If you need help on this, let us know.