Tested the 9x25Dillon with 10.2 grains Hodgdon CFE pistol powder from the Glock-20 with 6" LWD conversion barrel and Wolff non captive recoil rod and 22lb spring. Was shooting for 1800 fps (pun intended)
0.355" 115gr JHP (not recovered yet)
10.2 grains Hodgdon CFE Pistol
350 CCI LP (slightly flattened)
COAL 1.255"
Measured velocity 1702 fps (despite the leakage from the split casing) :-[
This was an older Double Tap 9x25 casing, the recovered casing split along the body (work hardened brass?), possibly releasing pressure slightly and reducing the velocity some. I'll test again to see if I get better results without a split casing.
Part of the issues working with unknown power values...I use older brass to find the weaknesses! ::)
Hodgdon shows a 357SIG using the 115 gr HDY XTP with 8.2 grain CFE loading doing 1431 fps @ 38,400 psi
(https://s20.postimg.cc/6zn1fv8z1/IMG_0421_zps987ed96d.jpg)
(https://s20.postimg.cc/vg57achfh/IMG_0422_zpscfd440bf.jpg)
Today's test of the Hodgdon CFE Pistol powder was better...no split case! Velocity was measured at 1698 fps, bullet stopped in the second gallon water jug, fragmented badly.
0.355" 115gr JHP (see picture bullet recovered)
10.2 grains Hodgdon CFE Pistol
350 CCI LP (slightly flattened)
COAL 1.255"
Measured velocity 1698 fps
(https://s20.postimg.cc/k3slskggd/IMG_0423_zpsfeba4f7a.jpg)
(https://s20.postimg.cc/blj5o8hnh/IMG_0424_zpsce8e455f.jpg)
Conclusion: LongShot powder is still a better choice in the 9x25Dillon.
I always considered a 357 SIG a 9mm on steroids. Whatever do I call a 10mm necked down to a 9mm?
Warp factor 9?
These were 115 grain JHP's, actually they may be from 9mm HST loadings, these were sold by Rocky Mountain Reloading as pulled bullets. ::)