General trigger pull question

[45Smashemflat]

Hey folks, hope your Sunday is going well.

I purchased an older 5 screw K38 CM as well as a similar age K22 CM awhile back. Both are shooter grade, not collector’s condition. I purchased them with the intent to use them, as well as leverage them to learn about the internals of these older Smiths.

The K38 has a pretty decent refinish done, but they blued the hammer and trigger. In talking to @Shotguncoach, he gave me the tip of finding a matched set on line, which I was able to do. However, the fit was a little sloppy, and you could see the replacement case hardened hammer moving a little side to side while pulling the trigger.

At this point, the DA trigger pull was a bit over 10#, and there was an occasional “lock up” and failure to return the trigger. Further dialog with @Shotguncoach (he’s the man!) led me to purchase some shims from triggershims. This I did, and installed the slimmest ones. (The next thickness up would bind up.). In this condition, the DA pull was over 12# and just felt “stiff.” I started to polish these on a whet stone, doing 100 strokes per shim, and re-installing. I repeated this several times and now have the DA down to just over 11#, and very smooth.

So, my question is, what is considered a “good” DA trigger pull for a general use, carry revolver?

 

[WR Moore]

OK, there are some threads on here that go into this in great detail. You can, with effort, get down to around 8 lbs with total reliability. However, there's careful work ahead. I'd start by pulling the cylinder and making sure the yoke barrel and it's recess are clean (brake kleen is your friend) and there's no severe run out (wobble) on the ejector rod. Now if your trigger is 10 lbs with a new rebound/trigger return spring, it'll let down somewhat with use to get near 8 lbs. However, standard factory practice is to have the hammer spring set so that if the gun is never properly lubed, it'll still spark off a primer.

 

[45Smashemflat]

I did check the stickies up top. I’ll work on my Google-fu and see if I can find more. I’m not looking to make this PPC low. As you point out, I do want reliability. I just don’t have anything to bench mark against.

 

[armorer951]

There are some very important things to check and verify if you are want to lighten the overall double action. I'm assuming this will be a range gun, and will not be carried.
First, the gun will have to be squeaky clean, especially the cylinder assembly. This requires complete disassembly with special attention to the extractor and cylinder internals.

Other items to check include making sure the hammer nose/ firing pin protrusion is correct. Verify that the rear gauge or "headspace" is also correct, and is as tight as allowed by specifications. Also, make sure there is adequate end shake for proper function (opening/closing, cylinder rotation and lubricants)....but not too much. Suggest .001"-.002".
End shake on the yoke assembly should be eliminated if you have the old style yoke with a screw pilot that is fit to the button on the yoke stem.

There are other areas that can be tweaked, but these are the main areas to check as you attempt to lighten the DA trigger. If you modify the mainspring and/or rebound spring, be sure you check the resulting SA trigger with a pull gauge to verify it is safe and there is no push off prior to firing. Modifying these components can lighten the SA pull as well.


Carter