Need Help

When you say your supply is 4500 psi understand that is pound per square inch. The gauge on your gun is in Bar. 3000psi is around 200 bar. Before you get confused do a little homework and get the conversion from PSI to BAR. This site has a good search tool. I often use it to find my own answers to questions that have been asked before. Give it a try and you will find the answers to your questions. Understand that this air gun thing is a technical hands on hobby, but fear not, the members here will help you with problems.