Germany

This is the Sturmgewehr 44 or StG-44, the grandfather of all modern assault rifles. Its appearance on the battlefield was nothing short of revolutionary. It fired the 7.92 x 33 mm Kurz (short) round . Soldiers loved the weapon because the cartridge packed enough punch, without making the weapon unmanageable because of recoil.

At first, Hitler was opposed to this kind of weapon, feeling that the bolt action rifle that he used in WWI was better. However, when he actually fired a prototype, he was so impressed, he wanted it named “Sturmgewehr” . This meant “storm rifle”, as in “taking the objective by storm”.

Many of these rifles were captured by the Russians, and may have been used as a starting point in the development of the AK-47.  Over 500,000 StG-44s were manufactured, and examples today can be purchased in the range of $20,000 to $40,000.

More Info: en.wikipedia.org