AK-47

The Automatic Kalashnikov 1947 is the oldest know surviving automatic weapon in the universe. AK-47s have been dug up in droves accross the galaxy and even in some other planes of existance. Due to their extreem reliability and relative avalibility, thanks to pre dark age peoples producing so many, the AK-47 and it's varients are the most common guns in the universe.

Pre Dark Age

 * AK-47

AMC

 * AMC-AK