Built in 1948 before full-scale mass production of Mikhail Kalashnikov’s famous rifle took off, the early prototype has a number of differences from later Soviet-made guns.
In the collection of the Russian state-run Kalashnikov Concern, the well-used vintage AK is one of a short run of 1,500 rifles made during the time of the Berlin Airlift. Using a stamped rather than milled receiver, the select-fire underfolder used a different trigger, has a hollow cylindrical charging handle and a short muzzle break. Kalashnikov says the latter feature was soon discarded as production moved forward due to high sound pressure.
In all, the early prototype looks rather more like the modernized AKM (Avtomat Kalashnikov Modernizirovanniy) which was adopted in 1959, than the milled-receiver AK-47 which was produced for more than a decade. Maybe they should have just listened to Mikhail in the first place.
source: http://www.guns.com/