I have a S&W K38 circa 1959 that I cannot "tune" for a lighter than seven pound double action pull. I have several other S&W double-actions that I can get down to a six pound pull and have reliable ignition with Federal primers. However, they are four inch guns whereas the K38 is a six inch and I want to keep the extra sighting radius advantage. Keep in mind that this is a "fun gun" that is dedicated to shooting steel bowling pins at fifty feet...it is used for nothing else. If I cannot get it down to six pounds, I may as well give up on this gun for my chosen game.
Notes: I have done all the polishing, etc. I need to find why and "fix" the gun requires such a heavy (yes I have aftermarket spring kits galore), mainspring to keep it from misfiring. I know my primers are seated correctly inasmuch as none of my other K frames are misfiring, even at six pound pulls.
I think what is happening is that the firing pin is striking the angled slot inside the firing pin bushing before it enters the firing pin hole and hits the primer...depleting some of its energy resulting in some light strikes. Layout dye applied to the hammer nose (firing pin) and the inside of the firing pin bushing seem to suggest that is what is happening I can see where the Blue is removed inside the slot, just above the firing pin hole. Also, I have been working with two different hammers and two different lengths of firing pins...light strikes occur with both. That suggests to me that the distance of firing pin noses in regard to the pivot hole in the hammers is NOT the problem. I suspect that the actual posistion of the hammer pin in regard to the hole in the firing pin bushing is a few thousandths off.
That era of K38 had no spring behind the hammer nose. I installed one anyway just to see if the spring would push the firing pin down and avoid striking the bottom of that little slot, but it made no difference whatsoever.
I have checked the hammer for any undue friction and hitting on the frame due to misalighment (shim on either side to straighten its travel), and verified with layout dye on the hammer. I also assembled the gun without the mainspring and rebound slide to verify no undue friction/rubbing by shaking the gun for and aft to see if the hammer would freely flop back and forth.
To those knowledgeable with S&W double-actions: Am I likely correct as to the nature problem...do I seem to be on the right track? Is there a remedy other than going to a different gun?
This is a gunsmithing question only...please do not suggest things like, "...exercise your hand so you can pull a heavier trigger...", or, " why do you need a pull that light?", etc. Please stay on topic.
Notes: I have done all the polishing, etc. I need to find why and "fix" the gun requires such a heavy (yes I have aftermarket spring kits galore), mainspring to keep it from misfiring. I know my primers are seated correctly inasmuch as none of my other K frames are misfiring, even at six pound pulls.
I think what is happening is that the firing pin is striking the angled slot inside the firing pin bushing before it enters the firing pin hole and hits the primer...depleting some of its energy resulting in some light strikes. Layout dye applied to the hammer nose (firing pin) and the inside of the firing pin bushing seem to suggest that is what is happening I can see where the Blue is removed inside the slot, just above the firing pin hole. Also, I have been working with two different hammers and two different lengths of firing pins...light strikes occur with both. That suggests to me that the distance of firing pin noses in regard to the pivot hole in the hammers is NOT the problem. I suspect that the actual posistion of the hammer pin in regard to the hole in the firing pin bushing is a few thousandths off.
That era of K38 had no spring behind the hammer nose. I installed one anyway just to see if the spring would push the firing pin down and avoid striking the bottom of that little slot, but it made no difference whatsoever.
I have checked the hammer for any undue friction and hitting on the frame due to misalighment (shim on either side to straighten its travel), and verified with layout dye on the hammer. I also assembled the gun without the mainspring and rebound slide to verify no undue friction/rubbing by shaking the gun for and aft to see if the hammer would freely flop back and forth.
To those knowledgeable with S&W double-actions: Am I likely correct as to the nature problem...do I seem to be on the right track? Is there a remedy other than going to a different gun?
This is a gunsmithing question only...please do not suggest things like, "...exercise your hand so you can pull a heavier trigger...", or, " why do you need a pull that light?", etc. Please stay on topic.
Last edited: