I just dug out my chronograph and ran the JSB 33.95gr 25cal over it. My kral puncher jumbo is only pushing them at 660-670fps. The bottle is full and I played with the lower adjuster but that was about all I could get out of it. This seams rather low compared to what I was expecting for it to put out. The accuracy seams to be great but I feel I should be getting more punch from a gun called “puncher”. I know I have seen people talk about opening up the ports but I have not researched it. I’m a machinist so doing the needed mods is not an issue.