It wasn't just the weed that brought down 2 Chainz' tour bus in Oklahoma a couple of weeks ago, the vehicle was also carrying two semi-automatic pistols, a 12-gauge pump shotgun and prescription painkillers according to official police documents.

As previously reported, there was a standoff between cops and 2 Chainz-plus-crew on the morning of August 22.

When cops approached the tour bus, they smelled weed and saw smoke. They wanted in, but those aboard locked the doors.

Apparently, one of the bus' passengers actually held a physical copy of the U.S. Constitution against the bus window ... "as if challenging officers" with his civil rights, according to a police statement.

Eventually, the bus was towed to a police training facility with the people still inside and cops gained entry, immediately arresting all passengers including 2 Chainz.