Is that what they are using for the acceleration charge (not the main charge!)?
Nitrocellulose can also be detonated with a properly brisant primary charge, which nitroglycerin is quite capable of being.
Typically Nitrocellulose (aka gun cotton, and the primary ingredient in most smokeless powders) won't detonate on it's own, but it's a very different beast from nitroglycerin.
[https://en.wikipedia.org/wiki/Table_of_explosive_detonation_...]