View Full Version : Colt M1909 question

January 26, 2009, 04:46 PM
I have question reference the Colt Model M1909. I have one, ser # 46,XXX, with all the appropriate matching markings that is .45 ACP and not .45 Colt. It will not chamber the long colt, but shoots great with half-moon clips and the acp ammo. I'm curious if there was any official program to have some of this pistols changed to accept .45 acp or perhaps someone along the line changed out the cylinder. Any thoughts?


January 26, 2009, 06:51 PM
If it is really a 1909 (marked on the frame as such, with the appropriate lanyard ring) and not a 1917, someone may have swapped out the cylinder. If all the numbers match up and it does not say Model 1909 on the frame, it is probably a 1917.

January 26, 2009, 06:57 PM
All the numbers match, to include the lanyard ring on the backstrap - where it says M1909. That's why I was curious if there was ever any rechambering program with the M1909.

James K
January 26, 2009, 08:05 PM
I have never heard of any conversion program. Do the chambers have shoulders so the .45 ACP will function without clips like the M1917? If so, someone swapped cylinders no matter what the numbers say. If not, someone may have just cut the back of the cylinder down like was done with the .455 Webleys to use .45 ACP with clips.


January 27, 2009, 08:05 AM
The cylinder won't support acp without the half moon clips. The round will fit in the cylinder, but the star gear doesn't engage to extract the fired rounds without the use of the clips.

January 27, 2009, 01:26 PM
I have never heard of a "program" to refit the 1909 with 45ACP cylinders, but it wouldn't surprise me one bit if the US Army did it just as a matter of fact to bring the revolver into then-current spec.

The ejector needs the half-moon (full moon/third moon) clips to work. What Jim was referring to is whether or not there is a headspacing shoulder at the appropriate place in the chamber (as you would find in a cylinder originally chambered for 45 ACP) or does it look like the chamber could be a long smooth tube (as you would find in a cylinder that had been rechambered from 45 Colt to 45 ACP). I had a 1917 that had no headspacing shoulder in the chamber.

January 27, 2009, 01:44 PM
Thanks for clearing that up. The cylinder has a headspace shoulder that stops the insertion of a .45 Colt round but accepts the .45 ACP.

Jim Watson
January 27, 2009, 02:37 PM
Then it has a 1917 (or commercial equivalent New Service) cylinder.
If the .45 Colt cylinder had simply been cut to clear moon clips, it would still accept a .45 Colt cartridge (but with excess headspace due to the wide rear gap.)

There is mention of such a gun in Henry Stebbins' book Pistols, a Modern Encyclopedia. One of his friends describes having an ACP cylinder fitted to his New Service so he could take advantage of issue ammunition.

James K
January 27, 2009, 05:07 PM
Colt made the New Service in .45 ACP caliber, primarily as a target model for the Service Cartridge matches, in which both revolvers and autos could be used. This was in addition to the so-called Model 1917 civilian version.

But the military Model 1909 was made only for the .45 Colt, even though the military used it only with the Model 1909 cartridge, which had a larger rim. Tedbrogden says that .45 ACP cartridges will fall through without the moon clips, but the original cylinder would not have enough headspace to take clips, so the rear has been trimmed down to take the .45 ACP and clips.

Ted, you can fire that revolver with .45 ACP and no problem, but don't try to use .45 Colt (Long Colt) or .45 Schofield in it or you risk a burst cartridge case, with damage to the gun and possibly personal injury.


Jim Watson
January 27, 2009, 05:16 PM
Well, the last thing he said was:

"The cylinder has a headspace shoulder that stops the insertion of a .45 Colt round but accepts the .45 ACP."

So I figure it is an ACP cylinder. Nothing you could do about cutting a Colt cylinder to take ACPs on clips would keep a Colt cartridge from going in, even though the extra .020" headspace would be undesirable.

January 28, 2009, 01:21 PM
Thanks for the replies. I have shot this pistol often over the past 25 years with great success using .45 ACP and half-moon clips. It's a great shooter. I had just become curious as to why it used ACP instead of the .45 Colt. Sounds like it's purely a case of someone sometime replacing the cylinder. Sure looks authentic.

February 7, 2009, 09:09 PM
what about serial no on cylinder.