CAS TOPICS > The Darksider's Den

.45 Cowboy Special

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Does anybody know what the throats would be on a .45 ACP cylinder?

The reason I ask is because my 3rd Gen Colt's regular .45 Colt cylinder has .455 - .456" diameter throats.  If the .45 ACP has .451 - .452" throats I bet the Cowboy Special could be a tack driver.

I can give you two sets of dimensions for S&W .45 ACP revolvers.

* I have had only one newer Model 25s with tight Ø.453 throat openings at the front of the cylinder, but most were Ø.454 
* I had fixed sight 1950 Model 22s with Ø.454 throat openings at the front of the cylinder.
* I have had Model 1955 S&Ws (later called Mod 25) with Ø.453 throats   (corrected per mister QUALITY CONTROL...AAAARGGGH)
* I currently have two unmounted spare cylinders for M1950, M1955 or Mod 25s (basically Model 22s or 25s) with Ø.454 openings   (corrected per mister QUALITY CONTROL...AAAARGGGH).  I have those spares because I used to fit an extra cylinder in .45 Colt to Model 25s, 1950s or 1955s, I have those two left, I may have cranes for them as well.  I would have to look.
* Most if not all of the .45ACP cylinders started out with a Ø.482 chamber opening at the rear
* The .45 Colt chamber is Ø.487 to Ø.489 at the rear depending upon the reamer and the Ø.454 throat is perfect for them.
In the S&W the .45 ACP chamber has the headspace step the case mouth butts up against, the .45 Colt chamber has the typical revolver leade and throat which is a gradual transition.

So there is no short answer for a S&W.  But all actually shot very well, I really couldn't tell much difference between the Ø454 and Ø.453 throats, especially with lead bullets.  Out of a Ransom Rest with match 185gr or 230gr jacketed bullets (if you squinted real hard) the accuracy might have been 1/2" better at 25 yards and at 50 it was a wash again.  The previous was probably a fluke, but the older 1950 barrels were reputed to be more accurate, I never proved it with a Ransom Rest.

As I said 30 or 40 years ago adding a .45 Colt cylinder was a common "conversion" or cylinder addition.  Finally S&W started making the 25 in .45 Colt, I don't know if you could get one with two cylinders except from the Performance Center and those were special order.

I don't know if you personally could tell the difference between the larger and smaller throats especially with Lead Cowboy loads, either way, enjoy them.

I can send pictures with gauge pins if you wish, but I'm not home for a few more days now.  I just have files on my drive I carry with me.



--- Quote from: Mako on April 15, 2024, 09:27:59 PM ---... (later called Mod 25) with Ø.253 throats [/li]
[li]I currently have two unmounted spare cylinders for M1950, M1955 or Mod 25s (basically Model 22s or 25s) with Ø.254 openings.  ...

--- End quote ---

Is this what they call the new math?  ;)

Sorry, I can't help it, I was in quality control for 25 years.


Baltimore Ed:
My 625 smith [.452 boolits] is very accurate. When I bought a beautiful used 45colt Anaconda I found that it patterned instead of grouped. Why I got a deal. After much experimenting I eventually discovered that .454 boolits would group, any other diameter would pattern.


--- Quote from: Baltimore Ed on April 16, 2024, 08:22:34 PM ---My 625 smith [.452 boolits] is very accurate. When I bought a beautiful used 45colt Anaconda I found that it patterned instead of grouped. Why I got a deal. After much experimenting I eventually discovered that .454 boolits would group, any other diameter would pattern.

--- End quote ---

Five questions:

* Have you measured the diameter of the exit throats on the 625?  I'm curious as to the size.
* And, do you know what general date the revolver was produced/purchased?
* What diameter bullets were you trying in the Colt before you settled on Ø.454?
* I'm assuming those were lead bullets at the Ø.454 diameter, what weight and bullet shape?
* Have you measured the diameter of the Anaconda's chamber throats?
I am not a SAA expert, but I do have one 1st Generation .45 Colt made in 1896.  The only other SAA pattern pistolas I have are a pair of USFAs in .38 spl the kids used.  Too bad they are out of business now.

This I do know:

* The Gen 1 SAA  used Ø.454 bullets (Lead of course)
* Gen 1 ran through 1940 
* Gen 1 rifling groove diameter was Ø.454
* In 1956 with the advent of the Gen 2 the groove diameter was changed to Ø.452 (some say Ø.451) 
* There have been discussions and arguments by both collector and shooters over whether or not all Gen 2 cylinders have smaller throat diameters to accommodate the new smaller diameter bores.
* Gen 3 models began in the late '70s, again I don't know the groove diameter.  (Ø.451 groove diameters?)  Main difference was in the barrel threads and the cylinder bushing.
* There really isn't a 4th Gen of SAA, though some people will call it that because they went back to the removable cylinder bushing, Colt's doesn't differentiate and the collectors usually don't. Now to the Anaconda, I beg your patience, but I have a short story:
I suspect they were/are still using some of the same (old) tooling and equipment to drill and ream the cylinders for both the SAA and the Anaconda.  In 1998 during a tour of the revolver line they were using a multiple station (at least 3 to my memory) vertical boring/reaming machine (probably custom built for Colt's) with 6 spindles per station. They were using it as a vertical drilling and reaming machine.  It was ancient, it still had the pulleys on it to allow it to be run from overhead shafts.  But, I was told by the accompanying engineer  the machine had been "modernized" after WW2 to have it's own electric motor.  I remember it well because they were using it to only drill one hole at a time, and after the 6 chambers were drilled it was passed to another worker to the right and then he reamed the chambers one at a time.  It was set up for the Anaconda, but I was told they also did SAAs on it.  I remember because of the inefficiency and I mentioned that they could use "DREAMERS" if they were only roughing the chamber and reaming the throat.  I was told by the worker on the machine very forcefully, "I DRILL, he reams".  I was waved off by the engineer I was with and the union steward who was with us began protesting me being there.

So that story was just to let you know I wouldn't be surprised if the tooling is shared between those two revolvers still and further more it wouldn't surprise me if the cylinder throats were Ø.454 or actually larger, which is why your revolver was more accurate with that size bullet.

So, the problem with not knowing the actual groove diameter or the throat diameters really crop up with jacketed bullets.  I don't know of any Ø.454 Jacketed bullets readily available for retail purchase, so you will be limited to Ø.452 max pistol bullets (not .45 Rifle bullets).  The pressures can spike when forcing a jacketed bullet through a small bore or even a small throat.  I don't think you will have any problem with Ø.454 bullets in a pistol with a .452 rifling groove and if that is what it likes then that is what you should shoot.  However I suspect your cylinder throats are probably Ø.454 or larger.

The S&W M1950 was a target pistol used by even the Army shooting team for the ".45 Caliber Pistol" portion of the Bullseye matches and Colts in .38 Special were commonly used in the '50s and '60s for the "Centerfire" Portion.  And, as I reported in a post above, many 1950 and 1955 (25s) had/have Ø.454 throats and they are very accurate.  However those match pistols were required at the time to shoot ball ammo and it was Ø.451 and they are very accurate.  There are a lot of factors and some weapons just like a certain weight or diameter.

I hope I didn't muddle too much or bore you.  Good shooting to you and if you have those measurements it would help me as a student of all things that go "bang".


PS  All content is subject to Quality Control checking and proofing by Abilene...


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