Tekashi 6ix9ine's getting 86'd from a boujee apartment complex ... and we're told it's because one of his armed guards allegedly got careless with a high-powered firearm.
Sources familiar tell TMZ ... when 6ix9ine heads to Miami, he usually crashes with Nelk Boys member SteveWillDoIt. We're told Steve's place -- part of SLS Lux Property -- put the hammer down on the rapper, banning him from their spaces.
According to a letter sent to Steve from attorneys for the condo association, obtained by TMZ, Tekashi's bodyguards showed up at the end of October, openly carrying assault weapons.
The letter says one of Tekashi's guards also "casually left his assault weapon unattended on his bag" and walked away from it briefly to talk with others.
The docs say the property association is "aware of the bounty placed on 6ix9ine's life" ... after getting out of prison "in exchange for information regarding others and the provocative antics of 6ix9ine," which the condo association thinks creates a dangerous situation for its residents, guests, employees and staff members.
It's unclear if there have been potentially dangerous incidents going down during his stays, but this clip obtained by TMZ shows someone with a gun waiting for him outside.
Sources tell us he's now on a banned list that includes a photo of Tekashi for apartment security to see. The attached message says, "If seen on property, do not check-in, do not approach and contact security immediately. "
We reached out to Tekashi and he said, "No comment."