Uploader here, this shows the trend towards less weight on the stock and more on the barrel, as that allows for greater accuracy (a more rigid barrel means the bullet can only go one way). But they are still in .223, a calibre adopted during the Vietnam war as it's the most profitable for the manufacturer: the cartridge is the greatest cost of general ammunition.

While they fought in Vietnam, the Mutts sold weapons to Poland, the ships unloaded in North Vietnam and their police shot the angry and betrayed veterans afterwards as 'the bad guys'. It was all about the money.