George Zimmerman was well armed last week when he was arrested for domestic violence ... according to Seminole County Sheriff's deputies who got a warrant to search the home Zimmerman shared with his girlfriend.
According to law enforcement, Zimmerman had stockpiled five guns and more than 100 rounds of ammunition ... including the 12-gauge shotgun his GF, Samantha Scheibe, claims he used to threaten her ... by shoving it in her face.
The search warrant ... obtained by TMZ .. shows in addition to the Kel-Tec shotgun, Zimmerman also owned an AR-15 semiautomatic assault rifle and three handguns.
Deputies also confiscated a pocket knife and a religious pendant.
Zimmerman is currently free on $9,000 bail ... his whereabouts are unknown.