Every gun I have ever seen or used has leaked no matter the brand. I use the $100 Novarossi Fuel gun and it leaks also. The more I use it throughout the day the less it will leak, I guess the o rings swell from the fuel. Me and my buddies usually just wait until the pit lap and use a fuel bottle to fill the gun, and then use the gun to fuel the car. This way the fuel isn't sitting in the gun any loner than a minute no matter what. If you simply fill the gun and let it sit more than likely it will be empty when you need it.