Frank is talking about Imperial Die Wax. It is good, and so is STOS, Ponsness Warren's loading press lube. Very little goes a long way. If too much lube is used, you'll get dents and deformed brass.

Best method of sizing brass, is to neck up .30/30 brass to .358", then back down in a .30/30AckImp(or .30/30) sizer, forming a new shoulder, to where it takes just a bit of pressure to close the lever, not much or it won't fire, then fireform. Necking this way will leave a 'false's shoulder for headspacing and the brass will fireform without stretching at the web. Another, easier method is to use a maximum .30/30 load, ie: factory load and lube the cases on a lube pad, then fire them. The lube will allow the case to slide back and form properly.

If you rely on the rim for headspace, the case will stretch at the web and case life will be shot- ie: 3 to 8 firings. Formed properly, it will last almost indefinitely - if the necks are annealed every 4 to 6 shots.

I always use a near max load for fireforming (as PO Ackley instructed) - the brass forms perfectly with one shot without stretching at the web, if lubed, or the false shoulder is provided. Easy stuff - without complications.