Higher nitration NC is certainly a high explosive. It has a detonation velocity higher than TNT.
Yeah... Opinions abound. But Hardt and the US military don't agree. Even high-nitration NC is processed on military ammunition facilities as if it were a deflagratory explosive. (I have spent a GREAT DEAL of time - years - in such facilities, so I'm not guessing what their opinion of it is...)
Nitroglycerine is added to double-base powders to increase the combustion velocity. FWIW, the military's interpretation MIGHT consider the combined mass required with the velocity of the detonator, in order to cause it to go high-order. It will NOT do that (even contained) when ignited by just heat.
Weirdly-enough, the US military considers black powder a high explosive (for processing/use setbacks)! Go fig'!! <grin>
Edited by lloyd, 25 February 2017 - 01:51 PM.