AC-15

AC-15 is a gun that becomes more powerful if the player has armor. If the player has no armor, it fires low-damage purple bullets with a high rate of fire. If the player is armored, it fires fast, piercing, high-damage blue bullets with a slower rate of fire and strong knockback.

Trivia

 * If the player has Gunknight Armor, it causes an unknown effect.
 * The gun's old pickup quote, "Metalled Gear", is a reference to the Metal Gear series.
 * The gun's name and pickup quote are a reference to the Armor Class (AC) system, used since the 1st Edition of Dungeons & Dragons to denote characters' defensive capabilities. Wearing armor would decrease the AC, making a character harder to hit, which is why armor increases the gun's power.  The gun's description of an "unintuitive system" refers to the THAC0 (To Hit Armor Class 0) system used in 2nd Edition, which gave numbers to each character class that they would have to roll on a die to hit an armor class of 0, reducing the "to hit" number if the AC was greater than zero, and raising the "to hit" number if the AC was less than zero.  The system was complex, which led to later editions having players roll dice against the AC value itself, rather than using the THAC0 number.
 * If the player has no armor and opens a chest containing the AC-15, it will briefly take on its upgraded appearance before changing to its normal form.
 * The gun's synergy with Void Core Assault Rifle may be a reference to the Armored Core series of videogames.
 * AC-15 shines while the player is armored.