It's not the first time the militairy was found fueling the black market. I've read and written about it before, now again:
It would appear that Brittish troops routinely take guns back with them as trophies. These are not to remain in their personal posession and have to be deactivated. But smuggling live weapons and explosives back from Afghanistan isn't a unique event either, nor is "misplacing" ammonution and trying to sell it off later something that doesn't happen.
One royal marine was found to be in posession of various rifles, at least one AK-74, a rocket propelled grenade and a mortar.
Another one, Christopher Trussler, of the Princess of Wales's Royal Regiment was caught trying to sell issued ammonution and claimed he could also get a re-activated AK-74 ...
The list goes on and can be found here.
If only the police and the military can legally have guns, criminals will still have them as well. A black market will ALWAYS rise to suply the need created by a prohibition; wether it's drugs, underage pornography or firearms.