My Steel Challenge load “powder puffs” is 3.5gr. VVN320 with RMR 124gr RN @ 1.115 OAL. 850fps. I use a softer recoil spring (can’t remember lbs) in my shadow 2 – 100% reliable, same for JP5.
If I’m not feeling lazy, I’ll drop to 3.3 – 3.4 gr with the same other data for my JP5, it eats them all day. Have to use a really light spring in S2 to keep cycling.
Good luck.
