The Colt double action story starts in 1877 with the Colt Lighting.
This was "sort of" a DA version of the Colt Single Action.
In 1889 Colt invented the world's first DA swing-out cylinder revolver with the Colt Model 1889 New Navy Model.
In 1892 they refined the design with the Model 1892 New Army & Navy.
In 1908 Colt perfected the design with the mid-frame Army Special.
Colt branched the design upward to the large frame New Service, and downward with the New Pocket.
Since the smaller revolvers were very popular, Colt continued development with the Pocket Positive, and finally the Police Positive.
The Police Positive was modified to handle the .38 Special as the Police Positive Special.
These three models, The large New Service, the medium Army Special, and the small Police Positive would serve as the basis of all Colt revolvers up until 1969.
In 1927, Colt changed the name of the Army Special to the Official Police, and put a 2" barrel on the Police Positive Special calling it the Detective Special.
All three frames were offered as target pistols. The large frame as the Shooting Master, the small frame as the Police Positive Target, and the medium frame as the Officer's Model.
Just before WWII, the large New Service frame revolvers were discontinued, and Colt made no more large revolvers until the 1990's.
After WWII, Colt began to assign letter codes to identify their frames.
The small frame was now known as the "D" frame.
The medium frame was known as the "E" frame, and after a slight modification, as the "I" frame.
Since these are so similar, they are usually simply known as the "E&I" frame.
Post war, Colt began an upgrade to the line in the early to mid-1950's.
The first post-war upgrade was a Officer's Model with a better adjustable sight.
The first really new post-war revolver was the Colt 357.
This was both the name and caliber of the gun.
The 357 caused quite a stir in the gun world and was a first in many ways, including being the world's first .357 Magnum revolver based on a medium frame.
Introduced at the same time was a look-alike version, the Colt Trooper.
The idea was, the 357 would be Colt's premium holster gun, and the Trooper would be a budget model for law enforcement and those not wanting to spend the money on the high-grade 357.
In 1955 Colt's top salesman convinced the company that he could sell a "Super Premium" target revolver.
This was intended to be the finest DA revolver in the world.
Due to the growing popularity of the .357 Magnum, the decision was made to chamber the new gun in that caliber, and the famed, fabled Colt Python was born.
During the same time frame, Colt also introduced a pair of "D" framed aluminum revolvers as the Cobra and Agent.
In 1966 a new target style "D" frame gun, the Diamondback was introduced.
Looking like a miniature Python, it was a premium-grade revolver, but NOT made to the same standards as the Python.
In 1969, Colt was forced by increasing labor costs to discontinue all the older style medium frame revolvers except the Python.
The older style Colt actions were complicated, and required extensive hand fitting and assembly JUST to operate properly.
In 1969 Colt introduced a replacement for the older styles with an entirely new type of revolver, the Colt "J" frame Mark III series.
Again, Colt caused turmoil in the gun business with the most innovative design of the 20th Century.
The Mark III series were the first revolvers ever designed specifically for modern production methods.
Instead of hand fitted parts, the new design used "machine fitted" parts that were fitted by pulling a part from a bin, and test fitting. If the part didn't fit, a different part was pulled from the bin until a fit was obtained.
The Mark III was the first modern revolver to use a transfer-bar ignition, which eliminated extensive fitting of hammer block and "rebound" type safeties.
The Colt design was so good, every brand of revolver designed since uses a virtual copy of Colt's 1969 design.
The Mark III also made extensive use of "sintered steel" cast action parts.
The Mark III and later version Colt DA revolvers are quite possibly the strongest mid-frame revolvers ever made, due to Colt's high-grade forged frames and cylinders.
The Mark III medium frame series was intended to be an analog to all of Colt's older mid-frame revolvers, with a premium holster model, several "service" style fixed sight models, and a target model, the Officer's Model Match Mark III.
In the early 1980's Colt did an upgrade to the action and cosmetics of the Mark III series and introduced the Mark V series.
By this time, the fixed sight revolver was falling from favor with both the police and civilian shooters, so there were only two models of the Mark V, the Trooper Mark V and the 2" and 4" fixed sight Lawman Mark V.
In the mid 1980's, Colt did a purely cosmetic redesign of the Mark V and introduced it as the King Cobra.
This was merely the Mark V with a new Python-like barrel.
The King Cobra was the first time a new revolver was introduced in stainless steel first, with a blued version following a year or so later.
In the late 1980's early 1990's Colt was going through upheavals and models were discontinued, reintroduced, and discontinued again in a dizzying pattern.
Finally discontinued for the last time in the mid-90's, the all the remaining "D" frame small revolvers were gone.
In 1990, Colt introduced their first large frame revolver since the New Service. This was the Anaconda.
The Anaconda is basically an up-sized King Cobra design, using the transfer-bar ignition and sintered steel parts, but sill using Colt's forged and heat treated frames and cylinders.
In 1995 Colt introduced what was to have been a replacement for the small frame "D" series.
This new frame was the "SF-VI, which was made as the SF-VI, DS-II, and the Magnum Carry, Colt's first .357 Magnum small frame revolver.
The SF-VI series were down-sized versions of the King Cobra.
In 2000, Colt went through an upheaval in which the medium and small frame DA revolvers were discontinued.
Left were the Python and the Anaconda.
In 2004, Colt announced that production would be suspended on the Python and Anaconda so the factory floor could be cleared for installation of new production machinery.
Production was supposed to re-start in 2005-2006.
However, Colt quietly decided to stop all production of ANY DA revolvers, apparently permanently and an era of American gun making came to a close.
And now, some eye candy:
A rare 1954 Colt Trooper in .22LR.
Supposedly, only 2200 of these .22LR versions were made between 1953 and 1969.
The little known Colt 357.
Very similar to the Trooper, it's often called a "pre-Python".
The famed and fabled Colt Python.
The finest production DA revolver of all time, it was basically a hand-made gun.
This one is in satin stainless steel.
Another Python in a 4 inch version.
The Colt Trooper Mark III.
Virtually every DA revolver designed since has closely copied Colt's innovative design and production techniques.
This one is in .22LR.
