Glenn scored 3 kills, shooting down 3 might 15s while on interactive duty flying with Air force fighter squadron 51. That was his last rotation in combat. Earlier in Korea his call sign was magnet ass due his affinity for AAA flying ground support for his fellow Marines. Sadly you really have to dig find info on his war records or time as a test pilot.
People forget the Mercury 7 were all hero's before becoming astronauts.