Flame Crash

A Flame Crash (摩擦弾頭(フレイムクラッシュ)) is a type of bullet used by Academy City.

Background
The bullets are made of extremely heat resistant metal and have special grooves carved in them so that air friction heats them up to 2500 degrees. When the bullets pierce armor, they burn away the electrical circuits and the fuel tank inside. When fired in a large amount the bullets can envelop large areas in flames.

Battle Royale Arc
This type of bullet was equipped on the HsAFH-11 (Six Wings) when Academy City deployed them to District 11 to deal with the 5,000 mercenaries BLOCK tried to smuggle into the city. Using the Flame Crash the Six Wings shred through the mercenaries quickly, blowing many to pieces. In the end due to the assault only 100 or so got away along with BLOCK out of the original 5,000.