Do I understand correctly that you simply compressed fresh powder into a .22 hollow point? Or did you do the same with powder that was already loaded in a closed reactor?
Almost. Not a hollow point. I drilled a small hole in the rear face of a slug, put the fuel mix into it (about 50mg) and sealed the hole by pressing a very small ball bearing (stolen from a shower-door roller) into the hole. The idea being that when the slug hit the ball would slide further into the hole and confine and compress everything in the hole 'for an instant'. No reactors were involved, just fuel and slugs and a steel-plate target.
ETA - for Axil. This was not any kind of replication attempt, but an original 'free-standing frolic' driven by my own curiosity.