Although commonly misconceived as a .22 caliber gun, a deuce deuce is indeed a handgun. However, it is not .22 caliber. A deuce deuce is an Austrian made Glock pistol model number 22. The Glock 22 pistol fires .40S&W rounds, not .22 caliber.
Noun: Glock 22 Handgun
The deuce deuce was made famous by many rappers and musicians.
"And the deuce deuce in my bubblegoose"
-- Notorious B.I.G.
"About to get loose with the deuce deuce"
-- Ice Cube
"I got the deuce deuce in the trunk of my car, Oh yeah"