It's a Hurricane piston, I'm almost certain the piston is on it's track, I think it might be the shimming. I'll have a look when our A/C get's hooked up (idiots forgot their manual so I've gotta wait till tomorrow), this heat really makes me not want to do anything.
As for grease, it's legit gear grease, don't remember what kind because my friend has it right now, but it was used on the piston grease rails and piston head...
I'd buy you all a beer for the help