S&W Model 66

[Warder-Lan]

Hi

I have a Smith and Wesson K Frame, Model 66 in 357 MAG that I am having a problem with.  The firing pin just barely touches the primer and only fires once in a while. The hammer nose (firing pin) looks ok; it is slightly round at the firing end.  Does anyone know what may be wrong?  All help will be greatly appreciated.

Thanks

Warder

[Hammerdown]

Hi

I have a Smith and Wesson K Frame, Model 66 in 357 MAG that I am having a problem with.  The firing pin just barely touches the primer and only fires once in a while. The hammer nose (firing pin) looks ok; it is slightly round at the firing end.  Does anyone know what may be wrong?  All help will be greatly appreciated.

Thanks

Warder

Hello Warder
It may be that the hammer nose Bushing is Mauled and Egg shaped from excessive dry firing, or perhaps it is time to change out the hammer nose  firing Pinitself. This is not a Huge problem any Good Gun smith can replace the hammer nose Bushing for you, as well as the Hammer nose firing Pin. Here is an early 66 I have, I hope this helps... Hammerdown

[Warder-Lan]

Hammerdown

Thanks for your reply.  I think you may be right about the bushing.  When the hammer is cocked the hammer nose firing pin moves up and down about 1/8 of an inch.

Warder

[gunblade]

It's normal for the firing pin itself to move a little when the hammer is cocked.  The bushing is actually installed in the frame where the nose of the firing pin pokes through.  The firing pin itself may be worn down and not making sufficient contact.   Also check the mainspring tension...the screw at the bottom front of the grip should be tight. 

[PawPaw]

One check I've always made: With the cylinder open so you can see the recoil shield, push the cylinder latch toward the grip with your thumb.  Cock the hammer manually, hold the hammer with your thumb and pull the trigger.   Let the hammer slowly go forward all the way into the firing position.   You should be able to see the firing pin protrude through the recoil shield.

Now, with the trigger full back, release it and watch the firing pin.  It should move back into the recoil shield as the hammer block lifts the hammer.

With a hammer-mounted firing pin it is common and proper for the pin to "wiggle" a little bit.

[Warder-Lan]

PawPaw

Thanks for your reply.  It works as you described.  I think the problem is that the hammer does not strike with enough force.  I can put a piece of masking tape over the primer hole of an empty casing, pull the trigger and the firing pin doe not penetrate the tape.  I think the main spring is too weak.

Ed

[spruce]

As stated above, there are several possiblities for this problem.

Another is that a previous owner, in an attempt to lighten the trigger pull, may have modified the mainspring by narrowing it (grinding some off the sides) or filed a little bit off the end of the strain screw (to reduce tension on the spring).
Neither is a good idea if you want a gun that fires reliably.

[Dee]

That model has a "strain screw". Someone could have shortened it, or backed it out to get a lighter pull. Check that. Also take the side plate off and see if it's gummed up with something like WD40. I have seen that MANY TIMES, and to the point the hammer will not fall fast enough to fire the primer.

[Warder-Lan]

Thanks to all for your help and information.  Problem turned out to be the main spring.  When I opened up the pistol and looked inside I saw that the main spring had been filed.  Guess it was filed for better trigger pull.

Thanks

Warder

[Dee]

Weeeeeeeeeeellllllll, I got close.

[S.B.]

Take your grips off this gun and check to see the main spring screw on the lower front of the grip frame, is fully tightened?
Steve

[pneuby]

The strain-screw is the first check, then the mainspring...as you found. However, here's a couple of checks I've done also, though it can be subjective.  Open the cylinder and cock it as PawPaw described. Place a brand new pencil through the barrel so that the eraser is where the primer would be. Point it muzzle-UP, and drop the hammer. That new pencil ought to launch a couple feet up. Okay, so that's the 'energy' check.

Now, press the tip of your off-hand index finger onto the pin bushing, then drop the hammer so that your fingertip takes the impact. It ought to smart a little bit, though not enough to make you scream. That's a good check for pin-protrusion.

While the latter can be done at a gunshow w/o raising too many eyebrows, you should get permission for the pencil check. Afterall, what goes up must come down, and that can make some folks unseasy.

[james]

I lightened the trigger pull of my 66 by backing off the leaf spring screw in the grip.  The next time I took it to the range it would only detonate about half of my reloads.   I tightened the screw and it became my most reliable pistol again.