Colt Cobra The Colt Cobra is a lightweight , aluminum - framed , double - action short - barrelled revolver , not to be confused with the Colt King Cobra . The Cobra was chambered in . 38 Special , . 32 Colt New Police , and . 22 LR . It holds six shots of ammunition and was sold by Colt from 1950 until 1981 . Product development and usage . The Cobra was made in two models : The First Model , made from 1950 - 1971 and weighing 15 ounces unloaded with 2 - inch barrel , and an improved Second Model , made from 1972 onwards , recognizable by its shrouded ejector rod , with an unloaded weight of 16 ounces . The Cobra is the same overall size and configuration as the famous Colt Detective Special and uses the same size " D " frame , except that the Cobra ' s frame is constructed of lightweight aluminum alloy as compared to the all - steel frame of the Detective Special . In the mid - 1960s , the Detective Special ' s and Cobra ' s grip frame was shortened to the same size as that of the Agent . The Cobra was produced in calibers . 38 Special , 32 Colt New Police , . 22 LR , and a rare few in . 38 S & W . The . 38 Special Cobra was available in 2 , 3 , 4 , and 5 inch barrel lengths . The . 32 caliber version was availble in 2 - and 3 - inch barrel lengths . The . 22 LR Cobra was available only with the 3 - inch barrel . Standard Cobras were blued with round - butt grip frames . The . 38 Special Cobra with a 2 - inch barrel was availble with a nickel finish at additional cost . Early models also had a square - butt option . Production subvariants . Colt " Aircrewman " . The " Aircrewman " was an ultra - lightweight version of the Detective Special constructed of aluminum alloy , and made from 1951 - 1957 for use by US Air Force aircrews . They are distinguished by the gold - metal Air Force medallion in the place of the silver - metal Colt medallion on the checkered wooden grips , as well as a cylinder made of aluminum alloy . Within two years of issuance , reports of cylinder and / for frame failure began to plague the Aircrewman and its Smith & Wesson counterpart , the M13 , despite issuing a dedicated low - pressure . 38 Special military cartridge , the " Caliber . 38 Ball , M41 " round . However , the cylinder fractures continued , and the weapons were eventually withdrawn from service . Colt " Courier " . The " Courier " was produced in . 22 Long Rifle and 32 Colt NP . It was made from 1954 - 1956 . Approximately 3000 were produced in the two years . Colt " Agent " . The Colt " Agent " was a lower - price version of the Cobra , featuring a less highly polished blue finish and smaller , simplified grips . The bottom of the Agent gripstock was slightly shorter than that of the Cobra . The original Agent weighed 14 ounces and was available only in . 38 Special caliber , with a 2 - inch barrel and blued finish . It was made from 1962 - 1979 . A slightly revised version of the Agent was released in 1973 with a shrouded barrel with a weight of 16 ounces . In 1984 , the Agent was briefly revived by Colt , this time with a parkerized finish ; production continued until 1986 . Colt " Viper " . The Viper was essentially a 4 " barrel version of the alloy - framed Colt Cobra in . 38 Special . Introduced in 1977 , it sold poorly , and was discontinued the same year . Ammunition . Some have recommended against the use of + P - rated . 38 Special cartridges in aluminum - framed Colt revolvers , as the Cobra was designed well before the " + P " designation . Others point out that + P ammunition is the same pressure as the regular pressure ammunition was before SAAMI lowered the standards in 1972 as a result of industry requests . They point out that the post - 72 loads are merely regular pressure ammunition labeled as " + P " . Some experts have done considerable testing so as to prove that + P . 38 specials are not truly hot loads . In the owners ' manual accompanying some post - 1972 Cobra revolvers , Colt recommended the use of + P ammunition for 2nd Model Cobra frames only , with the stipulation that the gun be returned to the factory for inspection every 1 , 000 rounds ( compared with a 2 , 000 - 3 , 000 round interval for the 2nd Model steel - framed Detective Special ) . The Cobra should never be fired with extreme - pressure + P + ammunition as there are no industry standards for such loads .