Also known as: ZIMMERMAN, 重ショ
SG-027 ZIMMERMAN
A handheld Shotgun for Armored Core Mechas that appears in Armored Core VI: Fires Of Rubicon.
It is infamous for its game-breaking strength in early versions, which was nerfed later on, but still powerful enough to be part of PVP meta.
Japanese players may call them 重ショ, short for 重ショットガン (heavy shotgun).