1917 Colt .45 acp to .45 Colt?

Calif Hunter · September 18, 2011, 04:50 PM

I have a 1917 Colt revolver that I picked up cheap because it had a bulged barrel. I replaced the barrel with one marked "New Service .45 Colt" as that was all I could find. It has been shooting fine with 250 or 255 gr lead bullets and Titegroup powder in .45 AR cases. The gun had been reblued, so it has no collector value - just a shooter.

When I was a kid, my uncle had a commercial 1909 in .45 Colt that I loved to shoot. I'd like the chambering to match the barrel markings, too, for safety reasons. Besides the cylinder and extractor, how much trouble and expense will it be to change from .45 ACP to .45 Colt?

James K · September 18, 2011, 05:30 PM

The most "trouble" will be finding a .45 colt cylinder and extractor for the New Service. If you do find one, make sure that you get it from someone who will guarantee condition, as some old parts are in pretty bad shape.

If you do get the cylinder and are lucky, it will fit right first time. If not, note that fitting a Colt cylinder is not really a job for the beginner. It can be tricky and most gunsmiths today have no idea what is involved.

Jim

oakfloor · September 21, 2011, 12:05 AM

I have this same revolver, and I looked high and low for a .44 special cylinder and barrel. Where did you find a .45 barrel? mine has a bulge too, I found another barrel for the bargan price of $300! Even numrich "out of stock" arms has nothing.

gyvel · September 21, 2011, 09:04 AM

Since, as you state, the gun has no collector value, merely stamp "auto" or "ACP" after the "45" on the barrel. This will obviate any safety concerns you may have.

**Mike Irwin** · September 21, 2011, 09:17 AM

Yep, stamping or engraving the barrel is probably the easiest solution.

Good thing is, though, that given the difference in rim thicknesses it's probably iffy at best if a .45 Colt would fire if placed in a gun chambered for .45 ACP.

If this is one of the late Colts with shouldered .45 ACP chambers, then the .45 Colt round shouldn't even fit in the cylinder.

James K · September 21, 2011, 10:35 AM

The headspace in the Model 1917's (Colt and S&W) is about twice that of a .45 Colt caliber revolver because the 1917's were intended to be used with half-moon clips. The .45 Auto Rim has an extra thick rim so it can be used in the 1917's without clips, but a .45 Colt cartridge (assuming the cylinder is reamed for it) will have too much headspace. If the round fires, it will be driven forward, then the back part will be pushed back. Depending on the pressure, the front part might stay where it is, and the cartridge case will be torn apart. Not good, so forget the idea of just reaming out the cylinder and shooting .45 Colt.

Jim

September 18, 2011, 04:50 PM	#1
Calif Hunter Senior Member Join Date: May 10, 2000 Location: La Palma, CA, USA Posts: 165	1917 Colt .45 acp to .45 Colt? I have a 1917 Colt revolver that I picked up cheap because it had a bulged barrel. I replaced the barrel with one marked "New Service .45 Colt" as that was all I could find. It has been shooting fine with 250 or 255 gr lead bullets and Titegroup powder in .45 AR cases. The gun had been reblued, so it has no collector value - just a shooter. When I was a kid, my uncle had a commercial 1909 in .45 Colt that I loved to shoot. I'd like the chambering to match the barrel markings, too, for safety reasons. Besides the cylinder and extractor, how much trouble and expense will it be to change from .45 ACP to .45 Colt? __________________ Calif Hunter

September 21, 2011, 09:17 AM	#5
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,380	Yep, stamping or engraving the barrel is probably the easiest solution. Good thing is, though, that given the difference in rim thicknesses it's probably iffy at best if a .45 Colt would fire if placed in a gun chambered for .45 ACP. If this is one of the late Colts with shouldered .45 ACP chambers, then the .45 Colt round shouldn't even fit in the cylinder. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

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September 18, 2011, 05:30 PM	#2
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	The most "trouble" will be finding a .45 colt cylinder and extractor for the New Service. If you do find one, make sure that you get it from someone who will guarantee condition, as some old parts are in pretty bad shape. If you do get the cylinder and are lucky, it will fit right first time. If not, note that fitting a Colt cylinder is not really a job for the beginner. It can be tricky and most gunsmiths today have no idea what is involved. Jim

September 21, 2011, 12:05 AM	#3
oakfloor Senior Member Join Date: December 10, 2009 Posts: 111	I have this same revolver, and I looked high and low for a .44 special cylinder and barrel. Where did you find a .45 barrel? mine has a bulge too, I found another barrel for the bargan price of $300! Even numrich "out of stock" arms has nothing.

September 21, 2011, 09:04 AM	#4
gyvel Senior Member Join Date: August 30, 2009 Location: Northern AZ Posts: 7,172	Since, as you state, the gun has no collector value, merely stamp "auto" or "ACP" after the "45" on the barrel. This will obviate any safety concerns you may have.

September 21, 2011, 10:35 AM	#6
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	The headspace in the Model 1917's (Colt and S&W) is about twice that of a .45 Colt caliber revolver because the 1917's were intended to be used with half-moon clips. The .45 Auto Rim has an extra thick rim so it can be used in the 1917's without clips, but a .45 Colt cartridge (assuming the cylinder is reamed for it) will have too much headspace. If the round fires, it will be driven forward, then the back part will be pushed back. Depending on the pressure, the front part might stay where it is, and the cartridge case will be torn apart. Not good, so forget the idea of just reaming out the cylinder and shooting .45 Colt. Jim