Paraffin wax is often used in (at least hypothetical) hybrid motors, mostly with N2O or HTP. Could it not, however, be used in a conventional configuration? Running at O/F of 12.4, 60 bar chamber pressure and 9.19 Ae/At, paraffin wax and ammonium nitrate achieve 2942.6m/s at sea level and 3211.5m/s in vac (using CEA). I don't know much about solid propulsion but I would assume that, being more volatile, it will melt/vaporise more readily and burn faster, but this could be useful (maybe a booster stage for ramjet propulsion). Why has this not been used before, or if it has, where? Somewhere colder maybe?