A senior Victorian member of the Comancheros had explosives and guns with silencers when he was arrested during raids on the bikie gang, police say.
The gang's vice-president Roberto Morando, 41, was arrested early on Wednesday when police swooped on clubhouses, homes, factories and businesses linked to Comancheros members and associates.
He has been charged with possessing explosives, handguns and silencers.
Police also allege the former bodybuilder was in possession of drugs including testosterone and morphine.
Morando, of Narre Warren South, appeared briefly in Melbourne Magistrates Court on Thursday and made no application for bail.
He was remanded in custody to appear again on May 15.
More than 570 police officers took part in Wednesday's raids, including a large contingent from the national anti-gangs taskforce.
It follows similar raids on Hells Angels clubhouses and members' homes in October.
Assistant Commissioner Steve Fontana said police had acted out of concern over a feud between the Comancheros and Hells Angels.