GMP previously confirmed they arrested a 20-year-old described by the force as “white British”, on suspicion of being concerned in the supply of Class A drugs at the scene on Friday.
Det Supt Joe Harrop, from GMP, said: “Our officers were met with an extremely dangerous situation on Bury New Road yesterday.
“Thankfully no members of the wider public or officers were harmed in the incident.”
He described the discovery of drugs and a gun as “a substantial find and it in turn prevents a potentially dangerous weapon and a significant amount of drugs from reaching our streets”.
He said they would “continue to target those involved in serious and organised crime to keep our communities safe”.
