Reloads with HS-6

Does anybody using HS-6 find a lot of unburned powder left in the case?

My 9x19 loads with 7.1 grains of HS-6 and 115 FMJ do not reliably cycle the action on a Hi Power. Unburned powder left in empties and action.

My 45 Colt loads with 10 grains of HS-6 and a 258 cast RF leave lots of unburned powder in the cases.

Should I be using magnum primers, or do I just have a bad batch of powder?

PED

hs-6 is a slow powder mainly used in magnum shotgun loads.
i would try a magnum primer in the 45 colt but don't think i would mess with it in the 9mm.
powders have a pressure zone that they like to burn in you just aren't there yet.
you might not be able to get there in the 9.