The Rockwell CZ53 personal minigun, otherwise known as the 5mm Man-Portable Minigun, is capable of firing 5mm ammunition at over 60,000 RPM with an ammo capacity of 120x 5mm round. The CZ53 personal minigun makes up for the small 5mm round by sending a hail of bullets toward its target. Its sheer size, coupled with its trademark sound, is enough to send anyone in its path running for cover. It's a great weapon for suppressing fire, letting others flank the unsuspecting enemy. When the Great War struck, it was already an aging design and was slowly being replaced by the more advanced CZ57 Avenger minigun. Later models of the CZ53 have six barrels linked into pairs, with four barrels on top and two on the bottom, a cage underneath the weapon to hold an ammo box containing 240 5mm rounds, and used in combination with a backpack. The first model was the favorite weapon of the Mariposa super mutants during the Unity's time, and allowed most or all of the super mutants to wield them effectively with only one arm.
This upgraded minigun has 50% greater durability than standard miniguns, and much greater firepower. It starts off in very good condition if chosen as a quest reward, but if it's obtained through pick-pocketing, its condition will be around half durability. It can be repaired with normal miniguns. Eugene, fully repaired, does almost as much damage as a fully repaired Gatling laser, while being much easier to find ammunition and repair materials for.
It is possible to receive two by injuring Brick enough during the escape for her to get killed by the super mutants. It can then be looted from her dead body along with Ranger battle armor. As long as at least one member of the Rangers survives, a second Eugene can then be obtained from Reilly.
Killing Brick (unless she is killed by the player character in either the super mutant attack on the roof or in the lobby) and taking it results in all of the Rangers becoming hostile, whether they witnessed her death or not. If one kills Brick, they cannot get caps from Geomapping with Reilly anymore.