Had seen a discussion on the velocity of a 397 at various pumps, these are four shot averages in .177 using 7.9 crosman premier hollow point
2 pumps 432 fps
4 pumps 561 fps
6 pumps 631 fps
8 pumps 684 fps
10 pumps 724 fpf.
this was done in my basement at about 60 degrees f, chrono was a FX wireless.
2 pumps 432 fps
4 pumps 561 fps
6 pumps 631 fps
8 pumps 684 fps
10 pumps 724 fpf.
this was done in my basement at about 60 degrees f, chrono was a FX wireless.