Model 64 Issues

[bernie]

A couple of years ago I picked up a Model 64 Smith and Wesson that was a Dept of Corrections trade in. I love shooting it but a couple of months back I began getting light primer strikes that would not go off. No problem, I put a new Wolff Main Spring and 15 lb rebound spring. Unfortunately the problem persisted. Then it hit me that the problem began about the time that I began using Remington Small Pistol Primers. So I tried 100 rounds of Monarch ammo and that seemed to rectify the problem. The Monarch gave me no issues whatsoever. However, the ammo with the Remington primers cannot very often get through a cylinder without getting a light primer strike. Then I tried 150 rounds of ammo with CCI primers and experienced no issues, except for the last cylinder full. You guessed it, a light primer strike!

What else may be wrong with it? I have historically not been a revolver guy but have really enjoyed shooting this ugly old revolver.

 

[Sovblocgunfan]

Strain screw not tight enough. That’s usually the first, and simplest, thing I would look at.

Otherwise, you don’t say whether anybody has done any work on the action. SA/DA? Or DAO?

 

[edwardware]

. . . I put a new Wolff Main Spring and 15 lb rebound spring. Unfortunately the problem persisted.

It could be pin power (springs) or pin protrusion. A new spring was exactly the right first step.

Next, check for crud in the frame recess preventing the pin from protruding all the way forward.

 

[bernie]

I forgot to mention that it is a da/as. I also forgot to mention that the strain screw is all the way in. I got it as a Virginia Dept. of Corrections trade in so I have no idea what was done before I got it, but the problem was not there when I originally purchased it. I will check for gunk when I get home.

 

[Riomouse911]

I had a firing pin tip break on a 629 classic after about 400 rounds... check the tip (or the pin if it’s frame mounted) to see if it’s intact.

Stay safe!

 

[AZAndy]

This Wolff mainspring you mention-- is it one of the ribbed ones? I've had to use a longer strain screw with those springs, since the screw lands right in the indentation for the rib. Had a 325 that gave me fits with light strikes-- even put in a longer firing pin, before I figured it out. McMasters part number 95235A507 will take care of it, and it's cheap.

Edit to add: If you don't feel like ordering the screw, PM me and I'll send you one. I use the Wolff springs often enough that I bought a dozen screws, so I have extras. I bet that fixes it.

 

[BSA1]

Is the firing pin striking all of the primers in the middle?

Off center primer hits indicate timing issues starting to happen.

DOC are not all gently used. Tower guards have to have something to play with during their shift.

 

[bernie]

Primers are all struck in the center, there does not appear to be any gunk in the channel that the firing pin and hammer ride into. I believe that AZAndy may have the answer. It is a ribbed mainspring. Thanks for the part number on the screw! I will order some tonight.

 

[bernie]

I thought it was fixed, but it wasn't. I put in the new screw, and put some more turns on the strain screw. It worked, and then it started piercing the occasional primer. I backed it off a half turn, the pierced primers stop, but the light primer strikes came back. Not as frequently but they are still there. Oh well...

 

[gotboostvr]

Pierced primers? I'd take a good look at the hammer nose/firing pin. That doesn't sound right at all. It should be nice and round.

 

[Sistema1927]

Sounds like it is time for a stock S&W mainspring.

 

[bernie]

The firing pin appears to be fine. It is simply hitting the primers very hard 95% of the time. The other 5% of the time it is an extremely light firing pin strike on the primer. The hard strikes are making a crater, and the light strikes are a divot. It is a very different look to the primer.

 

[gotboostvr]

I know you said you checked the firing pin channel, but I'd at least run a pipe cleaner and solvent through it.

You SHOULDN'T be blowing primers with the mainspring fully tightened. Definitely a bit of a head scratcher.

 

[Waveski]

It sounds as though something is binding , but only occasionally.
Have you eliminated the possible issue of hammer friction - contact with frame?

Double check to assure that the revolver is not loaded , then cycle the action while looking closely at the trigger from center rear. Is there any side to side movement of the hammer while is is in motion?

Look for bright spots on the contact surfaces of the internal components , indications of uneven contact pressure. Somewhere in the linkage there are parts that are not getting along with each other.

 

[Riomouse911]

My 686+ started binding up after a series of shots were fired, so I sent it back to S&W. It came back a few weeks later with a new ejector rod-star and the yoke straightened.

If the former users of your gun were cylinder-snappers there may be something out of alignment. (I never, ever do this and somehow stuff got out of whack with mine.)

Send it in and they’ll diagnose and fix the issues.

Stay safe!

 

[Eddietruett]

This Wolff mainspring you mention-- is it one of the ribbed ones? I've had to use a longer strain screw with those springs, since the screw lands right in the indentation for the rib. Had a 325 that gave me fits with light strikes-- even put in a longer firing pin, before I figured it out. McMasters part number 95235A507 will take care of it, and it's cheap.

Edit to add: If you don't feel like ordering the screw, PM me and I'll send you one. I use the Wolff springs often enough that I bought a dozen screws, so I have extras. I bet that fixes it.

I really like Wolff Springs and I've had the same situation in a couple of revolvers. Almost drove me crazy on the first one until I saw the obvious. Felt sort of dumb when I realized how easy the fix was. I've taken spent primers and put on the screw tip and it works fine as well.

 

[JONWILL]

Could be the primers. Are you sure they are small pistol. I bought a bunch of S&B primers that had the same problem.
I had some that took 3 or 4 strikes to set them off.

 

[bernie]

I don't think the problem is exclusively the primers, although the Remington's are giving me more trouble than other brands. The real symptom is inconsistent firing pin "force". About 5% of the trigger pulls are resulting in a firing pin strike that is light enough that you can see the difference in the primers after they are struck by the firing pin.