Rockwell designed the Avenger as the replacement for their aging CZ53 Personal Minigun. The Avenger's design improvements include improved, gel-fin, cooling and chromium plated barrel-bores. This gives it a greater range and lethality.
Rockwell designed the 5mm CZ57 Avenger as the replacement for their aging CZ53 personal minigun. The Avenger's design improvements include improved gel-fin cooling and chromium plated barrel-bores, giving it a greater range and lethality. It also has an ammo capacity of 120x 5mm round like the earlier versions of the CZ53 model. Later models of CZ57 have a high-speed motor, a cage underneath to put the ammo box and used in combination with a backpack.
One of many "mark II" versions of the weapons seen in the first Fallout, the Avenger has a good range for a machine gun and is deadly against light and medium armor. Along with the regular minigun, it has the highest rate of fire of any weapon in the game.
However, as with all 5mm weapons in Fallout 2, it suffers greatly from the poor Damage Resistance modifier of its only useful ammunition type, the 5mm JHP. This makes the weapon largely ineffective against the very heavy armor worn by many of the game's main antagonists. Critical hits mostly sidestep this problem though, dealing enormous amounts of damage due to their armor-piercing nature and the weapon's high rate of fire.
The Avenger has the highest damage per action point of any weapon in the game. This has only limited relevance since the weapon's effectiveness suffers greatly against heavy armor. Against unarmored targets, however, the Avenger can do the highest damage possible in the game: with the relevant perks (Bonus Ranged Damage x2, Living Anatomy) it can do over 800 HP of damage, with a theoretical maximum of 965 HP if every round hits the intended target. Lucky criticals on unarmored targets can exceed 2500 HP, with a theoretical maximum of 2885 HP.
Though not a bug peculiar to this weapon, all the burst weapons in Fallout 2 suffer from a bug whereby dead creatures obstruct burst fire as if they were standing up. Thus if a dead entity is located between the player and the intended target of his/her burst fire, that dead entity will block the majority of the rounds fired.
Interestingly, in v1.02, an Avenger loaded with JHP ammunition always causes no damage to K-9 Cybernetic dog in any indirect (shot through) attack, if K-9 is in company.
A remodelled version of the CZ57 Avenger appears in Fallout: New Vegas.