Yes, modern cyls will interchange if in the same caliber length group.
The 357 and 44 mag cyl lengths won't work of course; too long. But 44 spl, 45 ACP are very close to the TL cyl length and not need anything more than slight fitting as usual with cyl swaps for the correct model gun.
I have a 455 I replaced the cyl in with a post war, pre 1960 ACP cyl. No fitting needed. You want a pre 1960 cyl/ratchet so it has a right hand threaded extractor star. Or fit the TL star to the newer cyl. That way you can use the proper TL extractor rod, ctr pin and springs.
Recognize the TL ctr pin spring tensions it to the front. You need that because the TL recoil shield doesn't have the divot to cam the ctr pin forward on closing the cyl like all the ctr pins require on guns following TL production.
Here are my general notes on the subject:
44 TRIPLE LOCK EXTRACTOR ASSEMBLY AND CYL PARTS
BACKGROUND:
The 1908 .44 HE 1st model (triple lock) lacks the divot on the recoil shield because it has a 'front spring loaded center pin' which was changed on the .44 2nd model to a 'rear spring loaded center pin' that remains to this day.
Although Smith had the design of the .44 2nd model and subsequent .44s already perfected in the .38 1902 2nd year production after the engineering change, Smith went thru an exercise with quite a different design for their first N frame, the 1908 triple lock. Then switched to the 1902 design in 1915 on the .44 2nd model.
The triple (middle) lock cam plate is only for retracting the middle and front locks. It does not retract the ctr pin because the pin is spring loaded to the front and already retracted by its own spring. It's held in the lock position by the center and front locking bolt springs, against the ctr pin spring tension. The TL therefore does not have a divot in the recoil shield to act as a ctr pin ramp.
The divot on the recoil shield on other models is for retracting the ctr pin and is held in the locked position by its spring.
The other models I can think of off the top of my head are the M frame 2nd and 3rd model Ladysmiths, which have no divot on the recoil shield because they also have a ctr pin spring loaded to the front.
TL EXTRACTOR ASSEMBLY PARTS DIFFERENCES FROM LATER MODELS AND PARTS SUBSTITUTIONS:
These are things one can do to get a TL working again permanently or until the right parts are found. The 2nd Model and later N frame parts can be substituted as an entire unit or just certain parts, depending on which original TL parts are damaged or missing.
Although different, the TL extractor system can be adapted from the 2nd Model and later extractor assembly parts. TL parts are assembled differently but all the same overall lengths as later N frames with a few slight dimensional differences as outlined below.
1. The TL yoke cylinder axis tube is the same as later models.
2. The TL extractor rod:
The TL extractor rod has the large spring retaining collar machined integral to the rod necessitating the separate screw off knob on the front end to remove the rod from the rear of the yoke.
Later pre war rods for shrouded barrels have non-removable, integral knobs of the same size, but a separate spring collar for removability of the rod from the front of the yoke. Therefore a later pre war rod with integral barrel knob from the 1928 thru WWII period can be used in a TL with the caveat that the TL rod is slightly larger in diameter, .266" vs. .242" rod on all later models but works just fine.
3. The TL cylinder:
The main difference of the TL cyl from later model cyls is: the TL ctr pin is .020" larger in diameter at the rear end than later model ctr pins. Therefore the later cyl ctr pin hole in the extractor star will need to be enlarged accordingly. (Pg. 215-216 S&W 1857 -1945.)
The TL cyl is the same inside the center hole as other N frame cyls. The TL cyl is slightly longer than later cylinders by only .002" to .004" which only require cyl shims to use a 2nd model or later cyl, therefore a minor issue.
4. The key difference is the center pin:
The TL extractor center pin is sprung to the front, in the opposite direction from any subsequent Hand Ejector models which are all sprung to the rear. Hence you'll notice there is no divot in the TL recoil shield.
The TL ctr pin is the same OAL 4.080" to 4.090" (depending on final fitting to the front lock) as later N frames. But the critical difference is; the rear .687" length of the TL pin is .020" larger diameter than the rest of the pin, .119"+/- and .143" on the end, (later pins are .115"+/- and .122" on the end). Therefore to properly fit the hole in the TL star and in the TL recoil plate, a .687" long bushing by .143" O.D. must be pressed or sweated on the rear end of a standard N frame ctr pin. If you ctr pin is too short, this bushing can be left solid on the back end and installed only far enough to get the correct overall ctr pin length of ~4.085".
The later, and much easier obtainable, rear sprung center pin has a collar that must be moved about 5/32" forward. For our substitution scenario, simply turning off the collar in a lathe and replacing it with a 'E' clip in a groove cut in the new location will correct that. A 'E' clip in a groove is the factory method used to retain original TL front sprung center pin spring in the extractor rod along with a cupped collar between the "E" clip and the spring: .100" thick x .195" diameter, slightly cupped .010" deep on the spring side for the end of the spring to nest in. So retain and reuse it if you have it, on a replacement later style modified center pin. A simple washer of .100" thickness x .195" diameter will work just as well. The spring is tensioned between the back bored ledge in the extractor rod (see #3 above) and the "E" clip on the ctr pin.
TL extractor rod showing the integral collar, removable knob, and the ctr pin orientation. Notice the right end (rear) of pin is a larger diameter than the left end (front) of the pin. The tiny C clip on the center pin must be removed to remove/install the spring. There's also a .100" wide x .195" diameter spring retaining washer (which is missing in this 1st photo) that goes between the spring and the "E" clip. The gun will function w/o the washer or with a washer of the same size substituted:
Photo by Steelslaver
These are reproduced parts:
Photo by delta-419
Above: If the center pin is all you need for your TL, another alternative is having a new pin professionally machined to the above dimensions to put your TL extractor system back in business, and is not a complicated or an expensive proposition. I have names of some who reproduce these parts.
