Howdy Again
With all this talk about numbers of screws and pre-27 vs 27 I thought I would post a little bit of manufacturing history of The 357 Magnum and Model 27.
As I believe I said earlier, The 357 Magnum began life in as a follow up to the 38/44 Heavy Duty and 38/44 Outdoorsman.
The Registered Magnums were only produced from 1935 until 1938 when the factory registration program was suspended. The 357 Magnum (non-registered) continued to be produced with less customization up until production was halted in 1941.
The 357 Magnum Postwar Transition revolvers were produced from 1946 through the end of 1949. There were only 142 of these produced. This model would have included the re-engineered hammer block inside.
357 Magnum 'Pre-Model' 27. A collector friend of mine likes to say there is no such thing as a Pre-anything. Instead of a Pre-Model 10, the correct name is simply 38 Military and Police Hand Ejector. Likewise he insists there is no such thing as a Pre- Model 27. The Standard Catalog of Smith and Wesson by Supica and Nahas does call out a Pre-Model 27. These are specifically those 357 Magnums manufactured from 1950 until Smith and Wesson adopted a Model Number system in 1957. Physically, this model would have had the new Short Throw Hammers, which replaced the old Long Throw Hammers.
This 38/44 Outdoorsman has the old Long Throw hammer.
This Model 27 has the Short Throw hammer.
This photo illustrates the difference. The Short Throw hammer on the Model 14-3 at the top of the photo is at full cock. The Long Throw hammer on the 38 M&P Target Model at the bottom of the photo is also at full cock. Notice the Long Throw hammer is angled back further than the Short Throw hammer. With any double action revolver the position of the hammer at full cock will be somewhat further back than the position the hammer reaches when it is released in double action. That is simply because of the way that double action revolvers work. Anyway, the engineers at S&W realized that the hammer spring of any revolver has stored enough energy at the double action release point to fire a primer, and any more rearward motion of the hammer is overkill. So the Short Throw hammer was designed to go to full cock at less of an angle than the old Long Throw hammers.
As an aside, even though I prefer the older models, I actually prefer the Short Throw hammers on all the newer models. The gullet between the main body of the hammer and the hammer spur is much deeper on the Short Throw hammers, and the knurling is much more pronounced. I find on a hot day my sweaty thumb is more prone to slip off the hammer spur of a Short Throw hammer when I cock it single action. Even on the hottest summer days, that just does not happen with the deep gullet and sharp knurling of a short throw hammer.
End of Aside.
Anyway, that's the short story for Registered 357 Magnums, Non-Registered 357 Magnums, 357 Magnum Post War Transition revolvers and 'Pre-27' 357 Magnum revolvers. By the way, almost all of the above are five screw models, four screws to hold down the side plate and one screw in front of the trigger guard where the spring and plunger for the cylinder stop live. The 38/44 Outdoorsman pictured above shows the four side plate screws. The photo below shows the screw in front of the trigger guard on a typical five screw 38. The side plate screw at the top of the side plate near the hammer was eliminated in 1956 during 'Pre-Model' 27 production.
OK, 1957 was a banner year for Smith and Wesson because a Model Number naming system was adopted. The 357 Magnum in all of its versions became the Model 27.
S&W would add a dash number to model numbers to signify significant engineering changes. Often these changes would happen at the same time across all the many different models. Sometimes there was a bit of lag time with some models as old stock was used up before the engineering changes were instituted for a specific model. Also, generally speaking, engineering changes were instituted as a cost saving measure, to simplify production and thereby cut down on manufacturing cost.
Let's take a look at all the engineering changes for the Model 27 and the dates they happened. (Source SCSW) The comments in parenthesis are my own comments.
Model 27 (no dash) 1957. Change to the model numbering system.
27-1 (1960): Change extractor rod, right hand to left hand thread. (this change happened about this time across all S&W revolvers. Previously, unless the extractor rod was firmly torqued in place, the rotation of the cylinder tended to unscrew the extractor rod slightly. This would make the revolver difficult to open up because the thumb piece could not shove the internal spring plunger in the extractor rod quite far enough to disengage the spring plunger under the barrel. Reversing the direction of the thread fixed this, normal cylinder rotation tended to tighten the extractor rod rather than loosen it.)
27-2 (1961): Cylinder stop changed, eliminate trigger guard screw. (This changed the Four Screw Smiths to Three Screw Smiths. This is a change that saved production cost. Drilling and tapping a hole adds production cost. In addition, eliminating the screw in front of the trigger guard eliminated two parts from the parts list; the screw and the spring plunger. Personally, I hate taking the cylinder stop and spring out of a modern S&W revolver. With the old design it was simple to install the spring by slipping it into the hole, followed by its plunger and the screw. Now, it is easy to mash the spring out of shape while trying to wedge it in position when installing the spring.)
The photo below shows a cylinder stop spring wedged in position between the frame and the cylinder stop. Easy to mash the spring out of shape when removing it or installing it.
(1967): 6 1/2" barrel discontinued.
(1968): Delete diamond grip. (Several of the photos above show a diamond shaped area on the grip around the grip screw with no checkering. A few pennies were saved by eliminating that feature.)
1969: Change to "N" serial prefix.
1975: Target trigger, target hammer, Patridge front sight, on 6" and 8 3/8" barrels, introduced with Goncalo Alves target stocks and case.
This Model 19-3 from 1975 has oversized Goncalo Alves target stocks:
1979: 3 1/2" and 5" barrel discontinued. 4" introduced with red ramp and white outline rear sight.
1980: Target stocks standard.
27-3: (1982) Eliminate cylinder counterbore and pinned barrel. (This is the pinned and recessed so often referred to. Purely a cost savings move. Eliminating the pinned barrel eliminated several assembly steps. A tighter fitting thread on the barrel was used so the barrel would not unscrew. Eliminating the recessed couterbores eliminated a machining step.) Small change in cylinder length to 1.57"
1986: Discontinue nickel finish.
27-4 (1988): New yoke retention system/radius stud package/floating hand.
27-5 (1990): Longer stop notch in cylinder.
1992: Discontinue 4" and 8 3/8" barrel.
27-6 (1993): Hogue grips, drill and tap frame, change rear sight leaf, change extractor.
1994: Model 27 discontinued.
27-7 (2000) Performance Center version/8 shot, built on the N frame-with floating firing pin and extended frame lug-Special.
As can be seen, sometimes engineering changes rated a new dash number, some years not.
P.S. My Model 27 pictured above is a 27 No Dash. It left the factory in 1959. It is a Four Screw. Three screws holding down the side plate, one hiding under the top corner of the Magna style grips, and the screw in front of the trigger guard is not visible in that photo, but it is there.