Huben GK1 target shooting from 15 to 100 yards accuracy test. my base fps is 800 with jsb 25.39 pellets at a 3500 psi fill and the slugs are a .249 size.
some numbers:
3500psi 25gn 811 fps
3500psi 34gn 750 fps
4000psi 25gn 807 fps
4000psi 34gn 746 fps
4500psi 25gn 800 fps
4500psi 34gn 731 fps
4500psi 36gn 704 fps