Iron Bullet

Iron Creation Magic: Iron Bullet (鉄創成魔法『アイアンブレット』) is an Iron Magic spell.

Description
With an open grimoire, the user forms a large iron casing around their arm and then thrusts their arm toward their target. Propelled by mana, the casing is launched from the user's arm and explodes on contact.

Trivia

 * This spell is unnamed in the manga.