I'm tinkering with a budget 25 cal Air Venturi Avenger with a few mods. I've been able to tune it to 2,500 psi reg pressure, and 1 turn on HS. I'm pushing 30 grain NSA slugs 1,014 fps for a good 24 shots or 3 mags and a standard deviation spread of +/-3 feet per second from average speed...