Good evening, I attempted to do a little painting this afternoon. I was going to put some primer on the hood of my project car. During my test sprays I encountered an issue. My gun was leaking all over and making a huge mess.

After some cleanup I found the gun is dripping from the between the air cap and the ring the secures in place. I have gotten it as tight as possible and it continues to leak. I am guessing I should be looking someplace else on the gun to fix this issue and am looking for advice.

Well, if that's where it is leaking then it has to be coming from where the fluid nozzle itself attaches to t the gun. Could also be leaking back from the nozzle tip if the needle is not seating because of minor debris at that tip. I'd start by pulling out the entire needle assembly, clean and gun lube all that. You've got the nozzle off at that point....soak that in solvent for a day, blow it dry,and take a manifying glass and inpect the nozzle hole. Look for anything that could be a crack.
Another area of leakage on turbine guns is the needle packing. Just ahead of where the trigger is you should see a small nut that surrounds the needle as it goes back inside the gun. Underneath that nut is your gun packing. Honestly, though, we our guns we rarely see this fail but it can happen.
Best thing to do before you attempt any of that is to flip a pic. or two up here so I can look at it.....