Snuff bullets suck. I think they are mostly just a novelty item, not really practical.
They do ocassionally leak and they tend to get clogged very easily because of all the moisture they are exposed to while sitting in your pocket. They are frustrating and disappointing to use in my experience.
Those small vials with a tiny spoon work much better. Unscrew the cap, scoop up desired amount, then snort powder off of scoop. Doesn't get clogged, doesn't leak, less moisture exposure and you have better control over the size of each bump.