[oldphardt]

Basic question: Which cylinder is correct for my 1917 Smith 45ACP. I am not a pistol smith but just a tinkerer. This pistol came to me as a box of parts - about a dozen parts short of a load. Problem - Which cylinder is correct? One has a length of 1.542 inches excluding the extension which goes up against the crane. The other is 1.537. The longer one's extractor alignment pins are 0.390 (inside of pin to inside of pin) with the shorter cylinder pins measure 0.403. I have an extractor setup for the shorter cylinder but no extractor for the longer cylinder. Ultimately I would like to set up a second cylinder for the 45 long colt but to head space it correctly I would need a slightly longer cylinder to compensate for the half moon clips thickness.
Second question: Does anyone know where I can get a Long Colt cylinder with extractor? I have tried the usual sources but end up with non working parts or just wrong parts. I am not willing to accept 0.030 inches head space.

 

[Hondo44]

Welcome!

I'm happy to say that the shorter cyl is the exact same length as my 1917 cyl. so you have a proper cyl with extractor.

Now for 45 Long Colt usage, there are two options:

1. you can have the same short cyl chambers reamed for the 45 Colt case. Just ream the chambers a bit short so the 45 colt cases do not rest on the face of the cyl, but rather extend out of the chamber the exact same amount as the 45 ACP case. This will provide the correct headspace as it currently does for the ACP case.

If you intend to use factory ammo, you'll want to use a reamer that provides a round crimp shoulder in the chamber, instead of the square shoulder used by the ACP due to its taper crimp. If you reload, you can taper crimp your 45 Colt cases and have a square shoulder. The 45 Colt rimmed cases will extract in the normal way with the existing extractor.

This dual chambering of the cyl also eliminates the need for modifying the frame lug in the lower right corner of the cyl window on the left side of the frame.

Of course this will negate the ability to load and shoot individual ACP rounds w/o using half moon clips, which no one seems to do anyway. One other minor consideration is "bullet jump" from the ACP case to the chamber throats. Some feel there may be some slight accuracy detriment. Others do not feel there is, i.e., same as the use of 38 Spl in 357 Cyls.

2. the 2nd option is of course a 2nd 45 Colt convertible cyl. This option was offered by S&W on a limited production Model 25-4 in 1977. The cyls were the same length, 1.530". Therefore the same frame lug worked with both cyls. The way this was accomplished was for the ACP cyl to be initially machined leaving a ridge on the outer edge of the rear cyl face. The half moon clips and full moon clips nest within that ridge.

That means you would need two new cyls: a standard 45 Colt cyl and a specially machined cyl for ACP. And also modify (easiest) or replace the frame lug to accommodate both longer cyls.

A much easier and less costly alternative is to have your other cyl reamed for 45 Colt as described above. And find an extractor for it.

I hope this helps and if you have questions, of course just ask.

Jim