In 1950 Colt introduced a lightweight aluminum alloy frame revolver called the Cobra. It was built on the same D series design as the Detective Special that was introduced in 1927.  Colt made the Cobra from the using raw forgings purchased from The Aluminum Company of America (ALCOA), and the alloy was a special one formulated for Colt for use in the Cobra. The material was proprietary and named Coltalloy. This material was also used in the Colt lightweight Commander model.

The Cobra was chambered in the following calibers: .38 Special, .38 N.P., .32 N.P., and .22 LR.  I am going to focus on the .38 special model. The .38 Cobra came in blued and nickel. it has 2″, 3″ or 4″ barrels. The 2″ barrel model weighed 15 oz until around 1972 when the weight went up to 16oz.

Here is an ad from 1954:

The Cobra which was a spinoff from the Detective Special,  had a few spinoffs of it’s own:

The Colt Aircrewman made from 1951-1957 for use by  Air Force Aircrews. It has gold USAF medallions instead of silver Colt medallions. it weighed 11 oz. They did not hold up well in service.

The Colt  Courier made from 1954-1956 in .22 Long Rifle and 32 Colt NP.

The Colt Agent was a cheaper version of the Cobra made from 1962-1979. It weighed 14 ounces and was available only in .38 Special caliber, with a 2-inch barrel and blued finish.

The Colt Viper was essentially made as a 4″ Colt Cobra in .38 Special. It was discontinued the same year.

In the  Shooting Times from March 1978 issue, writer Clair Rees included a side-box in a Colt Viper review that claimed just as the issue was going to press, Colt had announced on December 2, 1977 that it was discontinuing all of it’s D series revolvers (Detective Special, Viper, Diamondback, Agent, and Cobra). Colt stated that it intended to totally phase out the production of all D series revolvers by October 1978. Colt stated that it had made this cutback because it wanted to focus it’s resources on other lines.  Thus ended the Colt D series revolver.

From what I can pick up from various internet articles and other publications there were a few changes/modifications on the design, the below may not be 100% accurate:

Early 1950s: Full length grip frame. Narrow front sight.  Small rear sight notch. Shortened ejector rod.

Mid 1950′ s : Larger front sight. Lengthened ejector rod. Larger profile rear sight

1966 : Shortened grip frame.

1972 Shrouded ejector rod.

1973 Heavier barrel. Smaller low ramped front and rear sights .

Here is serial number information for the Cobra and it’s spinoffs:



Serial Number

Cobra Introduced



Aircrewman Introduced









Courier Introduced






Courier Discontinued









Aircrewman Discontinued









Agent Introduced





























A84900 -A99999



B60000 -B61700


































Viper Introduced



Viper Discontinued






There has been much talk about using +P in older revolvers especially the alloy ones such as the Colt Cobra.

What Colt says about +P ammo, off of Grant Cunningham’s website:

Post-1972 (shrouded ejector rod) models: The owner’s manual says that these guns are rated for +P ammunition. The manual calls for a factory (gunsmith) inspection every 1,000 rounds for the alloy models (Cobra and Agent), and every 3,000 rounds for the steel-framed guns (Detective Special, Police Positive Special, Diamondback.)

Pre-1972 (unshrouded ejector rod) models: None of the Colt guns with unshrouded ejector rods are rated by Colt for +P use. These guns, made prior to 1972, were sold before the advent of +P ammunition.

In my opinion, I shoot and practice with standard pressure 38 in my Cobra, but carry +P in it. I train with a few cylinders of the +P every once in a while. Why? Here is why I have that opinion on the matter:

Before the adaptation of the .38 special +P standard in 1974 there was .38 Special High Speed.

If you look at some old factory data compared to the new load data and new factory data, you can clearly see the .38 special load standards were higher than they are today. This data is straight out of books I own.


1958 Federal 158 grain lead 855 fps

1971 Federal 158 grain lead 855 fps

2013 Federal American Eagle 158 LRN 770 fps

2013 Remington 158 gr LRN 755 fps

2013 Winchester 158 Gr LRN or LSWCHP 755 fps

Reload data:

2007 book 158 grain lead 708-844 fps start

2007  book158 grain lead 781 to 967 fps max

High Speed / Modern +P

1971 Federal 158 grain lead 1090 fps

2013 Winchester 158 grain LSWCHP 890 fps

2013 Remington 158 gr +P LSWCHP 890 fps

Reload Data:

2007 Book 158 gr lead 781-938 start

2007 Book 158 grain lead 843-1037 fps max

In comparison in 1972 the FBI introduced their +P standard 158ge LSWCHP load @ around 1000 fps. ( According to others: The Law Enforcement Handgun Digest of 1972 has a velocity chart on p. 188, which shows 1014 fps for this load (W38SPD) it has since been rated in modern times @ 890 fps)

Most standard factory 158 grain lead offerings run around 740-790 fps while most standard available 38 special +P lead offerings run 900-950. With some manufacturers such as Buffalo Bore advertising +P at 1000-1250 fps.

In 1956 The USAF Ball M41 130 grain round going 725 fps was designed to replace the old .38 Special 158 grain ball round going 850 fps that was causing the issues in the Colt Aircrewman and S&W M13 models.  The problem was the M41 was scarce so airmen got a hold of whatever ammo they could find, some of it high speed. There were quite a few stretched frames and kabooms even after the adoption of the M41. The Air Force decided to scrap both the Colt Aircrewman and S&W M13. These were stripped down allow versions as well. The Aircrewman only weighed 11 oz as compared to the Cobra at 15 oz at the time.

So as you can clearly see, that over the years the standard has been lowered a bit even though alloys and materials have advanced in strength and durability. Obviously there are more quality powders, more choices, and more recipes. That is why I feel comfortable shooting certain +P offerings lightly out of my Cobra. There has been no evidence of premature wear on it. I carry 135gr +P  Speer Gold Dot for Short Barrel at 860 fps or 158gr +P LSWCHP at 890 fps.

My Cobra was manufactured in 1970, it has carry wear and other wear from years of use, but it still runs like a swiss clock and locks up like a bank vault. It weighs just around 18.5 oz loaded with my carry ammo and offers 1 extra round than current j-frames or my LCR.

Here is an ad from my 1971 Shooters Bible:

In the beginning I was pulling it in to the left, and I figured out it was the grip being too thin and curved and when I pulled the trigger my hand was compressing causing the weapon to come in to the left. Just something I needed to correct and get used to. A Tyler-T grip fixed this slightly but I needed more time with it, as I started to practice point shooting and aimed fire, it started to come in . I carry with both a speedstrip  and or an HKS speedloader which works well.

The trigger is beautiful. It is a crisp 2.6 lbs in single action. This makes for accurate aimed shooting out to 25 yards. The double action trigger is smooth and clean. I prefer it over the Smith’s. The only better double action revolver trigger I have shot is the Ruger LCR. The cylinder rotates counter clockwise as opposed to the Smith and Wesson revolvers that rotate clockwise. The cylinder release is also a pull rather than the push release of the Smith and Wesson’s. While I  prefer the push release of the Smith’s, I see no issue with this design.

Double action accuracy for a 40+ year old 2″ revolver is not bad.  From 12 feet with 158gr LSWCHP:

With 148Gr Wadcutters:

and with the 135Gr +P Speer GDSB

Point shooting accuracy is also very good. The revolver works well from the draw and has a nice feel in the hand allowing for accurate shooting on the move.

A classic revolver deserves a well made leather holster. So I purchased a Side Guard Quicksnap for AIWB carry. The holster is well made and I recommend them highly. You can visit the website here: Side Guard Holsters

The revolver also pocket carries well in cargo pants with a Desantis nemesis. However due to the grip design does not fit into a lot of jean pockets as the end sticks out slightly.  They do make aftermarket grips for them however. The other disadvantage is the exposed hammer. It does hang up on draw especially from the pocket, although shrouds do become available from time to time or the hammer can be bobbed. It also becomes an advantage during aimed fire in single action so you have to find what works for you.

After 40 years the forcing cone is in surprisingly good shape, it locks up tight on every cylinder, the rifling is still in tact, the ejector is not bent, and the release latch and star are in great shape and function properly . These are all some of  items you should check if looking at one of these classic revolvers.

Here is a how to on checking a used revolver: The Revolver Checkout

it is important, especially with the old Colt’s due to the lack of quality gunsmiths if Colt cannot help you. Grant Cunningham is one of those gunsmiths. he has a few articles on his website pertaining to Colt’s.  Another option for the do it yourself bunch is the Colt Double Action Revolver Shop Manual.

So if you are looking for a classic, lightweight revolver, with 20% more ammo than the j-frames don’t forget to check out the Colt Cobra or it’s tougher big brother the Detective Special. You can usually find some good specimens as these were often fired a little, carried a lot. Just make sure you check them out carefully. There are still many accessories and holsters available for these little six shooters.