The titular Mac-10 is a machine pistol with a two-stage suppressor. The semi-automatic pistol version of the weapon was banned in the US under the 1994 Assault Weapons Ban.
Over Wheezy's beat, Trippie Redd trades flexes about violence, woman, and wealth with Lil Duke and Lil Baby. The Ohio rapper told Zane Lowe that he was in the studio during his stop in New York City for Travis Scott's 2018 Wish You Were Here Tour. He was vibing with Lil Duke while Lil Baby was sleeping on the couch when Wheezy came in the studio. Redd asked him for a beat, then came up with the chorus. Once Duke had spat out rhymes, Redd woke up Baby to come up with a verse of his own. "He took damn near 30 minutes but he woke up out his sleep and got that out the way," said Redd.
The ! album title was inspired by former collaborator XXXTentacion's ? record.