45 Colt in 1917 S&W

[PeteLongstreet]

I have a 1917 Smith that will chamber 45 Colt but the rim thickness leaves a pretty good gap between the cartridge base and the shield. The firing pin protrudes enough that it might fire but I'm thinking the setback might damage the gun. Any suggestions on how to make this combo work safely? I was thinking about grinding a set of half moon clips to space the rims back.

 

[Mister Heavyhand]

Stay with full moon clips and 45acp. You only get one set of hands.

 

[GAgunLAWbooklet]

When a revolver fires, does the cartridge case slide out of the chamber and impact the frame of the revolver?
Or does the brass case expand and become a friction-fit that adheres to the walls of the chamber and not move until it is manually extracted seconds (or minutes) later?

 

[jeep78]

This is a case of way out of spec headspace. Can it be done? Maybe. Should it be done? Nope.

 

[GAgunLAWbooklet]

what does "headspace" means on a revolver that uses straight-walled, rimmed cartridges (or clips over the rims of ACP rounds), anyway?

 

[Mister Heavyhand]

Chambers on the cylinders are machined to headspace on the case mouth for ACP if no moon clip. 100 year old revolvers such as these may have corroded / worn cylinders. OP wants to know if he can shoot long colt in a 45 ACP cylinder. Bad idea in my book.

 

[CQB27]

Chambers on the cylinders are machined to headspace on the case mouth for ACP if no moon clip. 100 year old revolvers such as these may have corroded / worn cylinders. OP wants to know if he can shoot long colt in a 45 ACP cylinder. Bad idea in my book.

Many 1917 Smith revolvers have had the cylinder chambers reamed to accept longer case cartridge 45 Colt. Some even purchase 455 cylinders and have them reamed to 45 Colt and end up with a 45acp/45 Colt conversion.

http://smith-wessonforum.com/s-w-ha...60789-model-1917-commercial-45-long-colt.html

The OPs revolver may be one that has been converted. At any rate a revolver built for a 45acp SAMMI Maximum Average Chamber Pressure of 21,000 psi can certainly withstand a 45 Colt with a SAAMI maximum average chamber pressure of 14,000 psi. The question is have the cylinder chambers been reamed to accept 45 colt.....or is the cylinder a very early model that some say (a bit of controversy exists about whether or not early "charge hole" cylinders even exist when it comes to S&W 1917s, as opposed the Colt 1917 which have charge hole cylinders in the early versions and chambers in the later. ) has "charge holes", i.e no step machined to headspace the cartage, or chambers that were originally built for 45acp, and later reamed for 45 Colt.

EDIT TO ADD: I just watched the Hickcok45 video and the Colt 1917 he is shooting is an early model that would have shipped with the charge hole cylinder, evidenced by the GHS proof mark on the left side of the upper frame that was used in 1917 only. Later models had the Ordinance Flaming Bomb proof make.

 

[jeep78]

what does "headspace" means on a revolver that uses straight-walled, rimmed cartridges (or clips over the rims of ACP rounds), anyway?

.It means unsupported case wall. Get a properly fitter cylinder for it if you want to shoot that round.

 

[CQB27]

I have a 1917 Smith that will chamber 45 Colt but the rim thickness leaves a pretty good gap between the cartridge base and the shield. The firing pin protrudes enough that it might fire but I'm thinking the setback might damage the gun. Any suggestions on how to make this combo work safely? I was thinking about grinding a set of half moon clips to space the rims back.

Your revolver was originally made to shoot 45acp with or without moon clips. When loading without a moon clip there is a gap between the back of the cartridge and the blast shield, enough that you can see and hear the rounds rattle a little when you shake the loaded revolver back and forth. You get the same effect when loading with a 45 Auto Rim cartridge. However, when you fire the revolver the rounds do not set back to any great extent, and firing without a moon clip is 100% safe with both 45acp and Auto Rim. If you revolver has been reamed to 45 Colt length, you are still going to have the rattle, because the cylinder began it's life built for moon clips. If the cylinder has been properly reamed, you can shoot 45 Colt fine without the use of a moon clip. There is at least one member over on the S&W Forum that has a 1917 with a 45 Colt reamed cylinder that shoots 45acp, 45 Auto Rim and 45 Colt though his revolver.

 

[gh1950]

When a revolver fires, does the cartridge case slide out of the chamber and impact the frame of the revolver?
Or does the brass case expand and become a friction-fit that adheres to the walls of the chamber and not move until it is manually extracted seconds (or minutes) later?

Depends.

In a low pressure load like the .45 Colt of .45 ACP, the brass does not expand sufficiently to form a friction fit. Especially with the .heavy and stout .45 Colt cases, fired at "normal" pressures, the brass will fall out.

Main problem with excessive headspace in a revolver is that the firing pin will not reach the primer, so it doesn't go "bang".

An example, with which I am very familiar is the .455 Webley. The ones in the United States almost universally have had the rear of the cylinder shaved so that they can use the .45 ACP with the 1917 moonclips (or .45 Auto Rimmed). Revolvers to which this has been done will no longer fire the original .455 Webley round, which has a very thing rim, without some sort of spacer.

what does "headspace" means on a revolver that uses straight-walled, rimmed cartridges (or clips over the rims of ACP rounds), anyway?

"Headspace" in a revolver is the distance from the base of the cartridge to the rear face of the frame. Even with moonclips, the headspace is measured the same way.

As noted, the 1917 will fire .45 ACP without the moonclips. What it won't do is eject the empty hulls because there is no rim for the extractor to act upon, the empties have to removed one at a time, it they won't fall out. The moonclip provided a surface to the extractor to act upon. Then there was a shortage of moonclips, so the 45 Auto Rimmed was developed.

SA revolvers tend to have long firing pins, and heavy main springs, and the headspace tends to be generous.