Invented by Mikhail Kalashnikov. Quite possibly the most popular assault rifle in existence, mostly because of mass proliferation.
7.62x39mm Soviet, 30-round clip. Has countless variants. Today it is black-marketted by terrorist cells (mostly because the AK is easy to make).
The AK-47 has been reported to have certain performances that surpass that of the Colt M16 series, and one reason is because the AK doesn't contain as many moving parts (therefore, maintenance is very easy). The AK-47 can also brave any type of harsh condition and environment.
There are ALL kinds of variants to the AK-47:
*AK-74 (5.45x39mm Soviet assault rifle)
*AKS-74u (5.45x39mm Soviet carbine)
*Saiga 12 (12g auto shotgun)
*Dragunov SVD (7.62x39mm Soviet sniper/infantry-backup rifle)
These 4 are just some.