I shoot my four S&W double-actions for non-defensive double-action shooting exclusively. Over the years I have tuned them for the lightest possible double-action trigger pulls with Federal primers exclusively. My current trigger pulls (via a Burkley pull gauge) are as follows:
S&W 686------6 lbs.
S&W 66-------6 lbs.
S&W 696------6.5 lbs.
S&W 14 (K38)..8 lbs.
I have done pretty much the same to all those guns, Wolff Spring Kits (lightened main spring and lightened trigger return springs), smoothed mating double-action surfaces, shimmed any hammer and trigger misalignments, cut two coils off the cylinder release springs, painted the insides with layout dye to detect any metal to metal contact, etc.
However, not matter what I try, the K38 (circa 1959), will produce light strikes if I go any lower than the .012 shim I put between the strain screw and the grooved Wolff ribbed mainspring. No matter what I do, it will not reliably fire my Federal primers...which is counterintuitive inasmuch as the lock-work of the four guns are virtually identical.
The two pounds difference has to have something to do with the hammer fall, but I can find no evidence that the hammer nose (firing pin), or the hammer is making contact with the frame prior to firing, and thus requires more force. I have tried a different hammer and longer firing pin, but that made zero difference in whether or not the primers would fire.
In theory, I should be able to get the K38 as light as the other three. From those with the requisite experience with S&W double actions, what can be the possible difference? Any suggested "cure"?
Please, no responses like: "Why do you need a trigger pull that light anyway?" or, "I always just strengthen my fingers...", etc. Please stick to the question as asked.
S&W 686------6 lbs.
S&W 66-------6 lbs.
S&W 696------6.5 lbs.
S&W 14 (K38)..8 lbs.
I have done pretty much the same to all those guns, Wolff Spring Kits (lightened main spring and lightened trigger return springs), smoothed mating double-action surfaces, shimmed any hammer and trigger misalignments, cut two coils off the cylinder release springs, painted the insides with layout dye to detect any metal to metal contact, etc.
However, not matter what I try, the K38 (circa 1959), will produce light strikes if I go any lower than the .012 shim I put between the strain screw and the grooved Wolff ribbed mainspring. No matter what I do, it will not reliably fire my Federal primers...which is counterintuitive inasmuch as the lock-work of the four guns are virtually identical.
The two pounds difference has to have something to do with the hammer fall, but I can find no evidence that the hammer nose (firing pin), or the hammer is making contact with the frame prior to firing, and thus requires more force. I have tried a different hammer and longer firing pin, but that made zero difference in whether or not the primers would fire.
In theory, I should be able to get the K38 as light as the other three. From those with the requisite experience with S&W double actions, what can be the possible difference? Any suggested "cure"?
Please, no responses like: "Why do you need a trigger pull that light anyway?" or, "I always just strengthen my fingers...", etc. Please stick to the question as asked.