Hoppy, I think you are out of luck with that powder. From Hodgdon:
"This spherical powder is a versatile shotshell propellant for heavy field loads, providing true magnum velocities with superb patterns."
and:
"LONGSHOT is the high velocity pistol choice in 38 Super, 40 S&W, and 357 SIG at lower-than-usual operating pressures."
Any CAS ammo with this powder will be very poor performance and lots of unburned powder. Your best bet would be to sell or trade it. Sorry!
I should add: In My Opinion. I've never tried it (and wouldn't).