Originally posted by Northrider
I found this post to be very informative and appreciate it a lot,and I am not trying to hijack it, but for me it brings up another question: Is there a way to visually tell the difference between the different frames? I know it sounds pretty elementary, but since I have only 1 S & W revolver (Model 19 in .357), I see posts about different frames and am left wondering how to tell them apart without carrying a book about S & W around with me.
If you've got a good eye for size, then you can usually tell them apart that way. S&W hand-ejector frame sizes in order from smallest to largest are as follows: M-Frame (long discontinued predates model numbers), I-Frame (discontinued), J-Frame (discontinued), Magnum J-Frame, K-Frame, L-Frame, N-Frame, Z-Frame, X-Frame.
The M-Frames have been discontinued for a very long time and aren't commonly encountered. They are very small and were only made as 7-Shot revolvers in .22 Long. The I-Frames have also been discontinued for quite some time but they do turn up occasionally and basically look like slightly shorter J-Frames. The true J-Frame has been gone since 1999, but they are still quite common, they are also quite difficult to tell apart from their slightly lengthened successor: the Magnum J-Frame. The M, I, J, and Magnum J-Frames are all generally considered to be "small" frames. The I, J, and Magnum J-Frames will also be five-shot guns if chambered for a .38 caliber cartridge (the I-Frames were never chambered for .38 Special, but were made in .38 S&W).
The K-Frame is obviously what your M19 is and is the smaller of the two medium frame sizes. Most K-Frames have six-shot cylinders but the 617 in .22 LR has a 10-shot cylinder. The largest/most powerful cartridge that has ever been chambered in the K-Frame is, AFAIK, .357 Magnum.
The L-Frame is the larger of the two medium frames and is usually found in .357 Magnum though some have also been made in 9mm, .40 S&W, .44 Special, and .44 Magnum. In .357 Magnum they may be found with either 6 or 7-shot cylinders and in all the larger calibers they will have a 5-shot cylinder.
The N-Frame is the large frame and has, at various times, been chambered in 9mm, .38 Super, .38 Special, .357 Magnum, 10mm Auto, .41 Magnum, .44-40, .44 Special, .44 Magnum, .45 ACP/.45 AR, .45 Long Colt, and .455 Webley. In any caliber from 10mm up, they will have a six-shot cylinder, 9mm and .38 Supers will have an 8-shot cylinder, .38 Special will have 6-shot cylinders, and .357 Magnums will have either 6 or 8-shot cylinders depending on the model and vintage.
The Z-Frame is the newest size and could be viewed as either a large or extra large frame. The only model made on the Z-Frame to date is the Governor revolver which can fire .45 ACP, .45 Long Colt, or .410 Shotshells.
The X-Frame is the largest and would most definitely be considered an extra large frame. The only two cartridges for which the X-Frame is chambered are .460 S&W Magnum and .500 S&W Magnum both of which have 5-shot cylinders.
The most difficult to tell apart are usually the I/J/Magnum J-Frames and the K/L-Frames. There really isn't any good way to tell the small frames (other than the very petite M-Frame) apart from each other at a casual glance since they're very close in size and often appearance. The K/L-Frames can sometimes be told apart more easily because there are certain features more common to one frame size than the other. For one thing, very few L-Frames have unshrouded ejector rods (the only one I know of is the M619) so any medium frame S&W with that feature is most likely a K-Frame (though this obviously doesn't apply to all K-Frames). Similarly, among models with shrouded ejector rods, full underlugs are more common on L-Frames while K-Frames more commonly had half-lug barrels. This, however, is not a hard and fast rule as there are some L-Frames like the Models 620, 520, and 69 which have half-lug barrels and some K-Frames like the 617 which have full-lug barrels.
Quite honestly, the sheer number of different revolvers that S&W has produced over the years makes visual identification by the untrained eye difficult. In addition to the large number of hand-ejectors that we've discussed, there are also many even older models which were top-breaks or tip-ups. If you're really interested in knowing about all the variations, the best reference is probably a copy of
The Standard Catalog of Smith and Wesson.