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.
Because of the ammunition (5mm JHP, not AP) and the number of bullets fired per burst (40), each one having possibility to score a critical, one can achieve the highest possible damage in Fallout 2 using this weapon, by having the right perks (Bonus Ranged Damage (2), Living Anatomy, Better Criticals), attack an un-armored living target (such as a dog) and scoring a critical that multiplies damage by 5, 5000-exceedings have been reported.
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.
The Avenger can become one of deadliest weapons in-game (together with the Bozar) with perks Better Criticals and Sniper (& 10 Luck); making it perform 40 shots, every one critical, each with 20% probability to cause instant death (due to 0-100 -> 20-120 critical hit calculations shift).