In 1971 the RVN with support from US troops launched a limited invasion, spoiling attack in to Laos. The purpose was to disrupt the ability of the PAVN forcing to operate the Ho CHi Minh tail and stage their spring offensives into South Vietnam , much like the previous invasion into Cambodia.
While in Laos this AK variant was recovered. Whats the big deal? Well. These were very rarely seen in RVN during the war. The AMD is a Hungarian made version of the AK. Designed for armored troops and paratroopers with its folding stock and shorter barrel.
Of course this wasn’t the only one to turn up in South East Asia.
Above, Pat MacGrath of IUWG Unit-3 holds an ADM.
Below is a picture of Donald Ramsey of Recon Team Delaware, MACV/SOG firing an ADM at the range.
How they got there? No doubt communist forces received them via their normal communist supply routes. SOG no doubt had them as part of their giant inventory of foreign untraceable weapons for use on cross border missions. The restrictions on US weapons was relaxed after a few years, but some teams still preferred to carry the same weapons of the enemy for a variety of reasons. To disguise their profile long enough to get an upper hand, to be able to use the enemies ammunition, to disguise sound signature, to leave combloc empty cases on the ground to make it harder to track them after a chance encounter firefight etc.