commygun
Member
I've been getting light firing pin strikes ( about one or two per cylinder) from my S&W Model 66. I replaced the mainspring with a standard power Wolff but the problem persists. Any thoughts about what the problem might be? Thanks.
Light strikes from a S&W
- Thread starter commygun
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rcmodel
Member in memoriam
Is the strain screw in the front of the grip frame fully tightened?
Some folks might think it is a trigger pull adjustment screw.
It isn't!
If it is tight but still misfires?
I might suspect someone cut off the end of the strain screw to lighten the DA trigger pull.
You might also clean real well under the extractor star using an old toothbrush.
Maybe unburned powder grains under they cushioning the blow??
Yea! That's pretty far fetched.
rc
Some folks might think it is a trigger pull adjustment screw.
It isn't!
If it is tight but still misfires?
I might suspect someone cut off the end of the strain screw to lighten the DA trigger pull.
You might also clean real well under the extractor star using an old toothbrush.
Maybe unburned powder grains under they cushioning the blow??
Yea! That's pretty far fetched.
rc
Last edited:
Elkins45
Member
Worn hammer nose? The firing pin should protrude about 0.06 IIRC
Lost Sheep
Member
Let me guess: Handloads?
You are not using Federal Primers.
CCI primers are reputed to be made of harder metal than most. Less prone to perforation and primer flow with high-pressure loads, but sometimes harder to ignite.
Federal primers are reputed to be made of softer metal than most. Less prone to misfires, but if using high pressure loads, can deform even to the extent of flowing the metal back into the breechface and firing pin hole.
What primers are you using?
Second guess: Does a second strike succeed in igniting the primer? It could be that the primer was not fully seated, thus the first primer strike's energy was absorbed by the energy of seating the primer. The second strike often succeeds where the first did not.
Note that even factory ammo sometimes is not as perfect as their QC office would desire.
Just wild guesses. I hope they help.
Lost Sheep
You are not using Federal Primers.
CCI primers are reputed to be made of harder metal than most. Less prone to perforation and primer flow with high-pressure loads, but sometimes harder to ignite.
Federal primers are reputed to be made of softer metal than most. Less prone to misfires, but if using high pressure loads, can deform even to the extent of flowing the metal back into the breechface and firing pin hole.
What primers are you using?
Second guess: Does a second strike succeed in igniting the primer? It could be that the primer was not fully seated, thus the first primer strike's energy was absorbed by the energy of seating the primer. The second strike often succeeds where the first did not.
Note that even factory ammo sometimes is not as perfect as their QC office would desire.
Just wild guesses. I hope they help.
Lost Sheep
rcmodel
Member in memoriam
A properly functioning S&W Model 66 will set off CCI primers, or any other primers till hell freezes over without a misfire.
There is something else going on.
I agree it could be improperly seated primers in handloads.
Or it could be excess end-shake.
Or it could be the brand of brass he is reloading.
See this about that:
http://www.thehighroad.org/showpost.php?p=6966298&postcount=1
rc
There is something else going on.
I agree it could be improperly seated primers in handloads.
Or it could be excess end-shake.
Or it could be the brand of brass he is reloading.
See this about that:
http://www.thehighroad.org/showpost.php?p=6966298&postcount=1
rc
OP
OP
commygun
Member
Comparing the 66 to my Model 19 I notice that the firing pin can rock back and forth much more in the 66 than in the 19. With both firing pins rocked forward the gap between the back of the firing pin and the hammer is over twice as large in the 66 compared to the 19. Is that significant? The misfires are occuring with a variety of factory ammo and the strain screw is fully inserted and has not been tampered with.
rcmodel
Member in memoriam
Probably not.
Depending on the dash-#'s?
My Model 66-1 FP is spring loaded down and has a lot of available up / down movement.
My Model 19-4 FP isn't spring loaded down, and has way less available U&D movement.
Did you check the strain screw for tight or filed off yet?
rc
Depending on the dash-#'s?
My Model 66-1 FP is spring loaded down and has a lot of available up / down movement.
My Model 19-4 FP isn't spring loaded down, and has way less available U&D movement.
Did you check the strain screw for tight or filed off yet?
rc
jdomin
Member
Grips?
If you have changed the grips on the gun with an aftermarket pair it might
make a difference on lite primer strike
If you have changed the grips on the gun with an aftermarket pair it might
make a difference on lite primer strike
OP
OP
commygun
Member
Possible. I put some rubber ones on. I'll have to see if the mainspring can drag against them.
OP
OP
commygun
Member
Rcmodel,
Reading your last post, do you mean your 66 firing pin has spring tension that holds it forward? My firing pin seems loose in the hammer, rocking back and forth freely.
Reading your last post, do you mean your 66 firing pin has spring tension that holds it forward? My firing pin seems loose in the hammer, rocking back and forth freely.
rcmodel
Member in memoriam
All S&W hammer noses have free up & down movement available.
Some S&W hammer noses are pre-loaded down by a tiny spring.
Some are not, and are free to flop up & down.
I have a 19-4 that isn't, a 66-1 that is, a 36 that isn't, a 1950 Target that is, a 49 that isn't, and a Victory model that isn't.
But regardless of that.
Whether it is or isn't would not cause mis-fires unless the hammer nose it moving up so far it is hitting the frame before it gets to the hole in the recoil shield.
rc
Some S&W hammer noses are pre-loaded down by a tiny spring.
Some are not, and are free to flop up & down.
I have a 19-4 that isn't, a 66-1 that is, a 36 that isn't, a 1950 Target that is, a 49 that isn't, and a Victory model that isn't.
But regardless of that.
Whether it is or isn't would not cause mis-fires unless the hammer nose it moving up so far it is hitting the frame before it gets to the hole in the recoil shield.
rc
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