I would have considerably more sympathy for Sgt Nightingale were it not for the fact that a very large amount of ammunition, clearly acquired over a significant length of time, was also found in his property.
He has got off bloody lightly in my view, and if you look at ARRSE, the general opinion seems to be that he deserves to be in prison for carrying out several criminal acts. Anyone else would right now be serving a minimum five year sentence.