Light Primer Strikes

[GypsmJim]

I have owned a circa 1953 Pre-14 for about 10 years. Its in very nice condition and shoots like a tack driver. I usually take it to an indoor range and have only fired it single action. This weekend I was outdoors and tried to shoot it double action. Every shot yielded a light primer strike and the rounds would not fire. They all fired the second time in single action and the strikes were normal.

What should I be looking at?

 

[Protocall_Design]

Sounds like too low tension on the mainspring. See if the strain screw is backed out. If not, maybe it needs a longer one.

 

[oldgranddad]

If I'm not mistaken, the hammer comes back a little further in single action than it does in double. This loads the main spring just a little more. I wonder if the main spring screw is set just on that edge where there's not enough force for double action but just enough for single. The first thing I would check is the length of the strain screw. Second that the area where it seats is clean allowing it to seat all the way and last, make sure it's screwed down tight. If none of that works, consult a good gunsmith. If you're not comfortable with anything I've suggested, go right to the last item (consult a good gunsmith).

 

[WR Moore]

It's worth checking the hammer spring tension screw. In fact the double action hammer fall is shorter than the single action hammer fall, however, neither may be your problem. It may be operator error, especially if you're new to double action firing.

The double action trigger press is supposed to be a firm steady press that you perform while making minor adjustments to your sight picture. If you're pressing the trigger very slowly to try to shoot gnat size groups, you may not be completing the trigger press (pinning the trigger all the way back). This can let the trigger move very slightly forward as the hammer starts to fall, setting up an interference between hammer and trigger that robs the hammer of the force needed to pop the primer.

I mention this because I've seen it many times and yes, I've been guilty of it myself now and then. You probably need to work on completing the trigger press. Easy to check, try a cylinder full with no regard for group size, just mash the trigger all the way back.

 

[oldgranddad]

It's worth checking hammer spring tension screw. In fact the double action hammer fall is shorter than the single action hammer fall, however, neither may be your problem. It may be operator error, especially if you're new to double action firing.

The double action trigger press is supposed to be a firm steady press that you perform while making minor adjustments to your sight picture.
If you're pressing the trigger very slowly to try to shoot gnat size groups, you may not be completing the trigger press (pinning the trigger all the way back). This can let the trigger move very slightly forward as the hammer starts to fall, setting up an interference between hammer and trigger that robs the hammer of the forced needed to pop the primer.

I mention this because I've seen it many times and yes, I've been guilty of it myself now and then. You probably need to work on completing the trigger press. Easy to check, try a cylinder full with no regard for group size, just mash the trigger all the way back.

I don't know about GypsmJim, but I learned something from this.

 

[GypsmJim]

The strain screw is all the way in and quite tight. Since I also have a 14-2 I took both of them apart and found that the strain screw of the revolver in question is 0.007" shorter. Since I don't know what the tolerance is supposed to be, I don't know if that's significant or not.

Also, I don't know if the gun ever had a "trigger job" in the last 60 years. By the very light turn line I would guess it wasn't shot that much.

The day that I had the issue it was cold and gloomy and I was too lazy to set up a target and roll out my "shooting bench on wheels". So, I was just shooting at tin cans. As a matter of fact, all I had that day were revolvers and I was shooting double action with all of them. This was the only S&W that malfunctioned. I don't claim to have perfect technique at my advanced age, but I DO learn something new every day.

 

[Protocall_Design]

You can hook a trigger pull gage under the hammer nose and see if the pull weight of the hammer is the same on all the guns. If the pre-14 is noticeably less than the others, that is the problem.

 

[GypsmJim]

You can hook a trigger pull gage under the hammer nose and see if the pull weight of the hammer is the same on all the guns. If the pre-14 is noticeably less than the others, that is the problem.

I don't have a trigger pull gauge, but I was just playing at my basement workshop and my "finger" could not detect any "significant" difference.

After taking the strain screw out following suggestions above, and reassembling the revolver, I loaded up 12 empty cases with primers only and fired them double action. The results now were different. 7 of 10 went off and had strikes equal to single action. 3 had light strikes. 2 needed to be fired a second time.

 

[Drm50]

99% of time it's the strain screw. Everyone shoots SA and tunes gun for it.

 

[GypsmJim]

99% of time it's the strain screw. Everyone shoots SA and tunes gun for it.

Got one on order.

Thanks to all for the responses.

 

[Jeppo]

Got one on order.

Thanks to all for the responses.

Someone much smarter than I came up with a brilliant workaround. Put a fired primer between the screw and the spring. It'll act as a shim and can't go anywhere.

That'll let you be certain the screw length is the issue.

 

[Seven High]

I am guessing that the revolver should be torn down and cleaned thoroughly. Old oil or grease can solidify and cause misfires in double action.

 

[CheyenneBodie]

If shooting reloaded ammo make sure the primers are fully seated in the primer pocket. I hand seat my primers using an RCBS priming tool--it makes a big difference-- especially with a revolver that has a light double action. Primers should be seated firmly to the bottom of the primer pocket. By so doing, the legs of the primer anvil are in firm contact against the bottom of the pocket. At the same time the primer anvil is forced deeper into the priming mix. This places a portion of the mix over the anvil point under '"dry compression" which increases its sensitivity to the optimum level.

 

[Eddietruett]

If shooting reloaded ammo make sure the primers are fully seated in the primer pocket. I hand seat my primers using an RCBS priming tool--it makes a big difference-- especially with a revolver that has a light double action. Primers should be seated firmly to the bottom of the primer pocket. By so doing, the legs of the primer anvil are in firm contact against the bottom of the pocket. At the same time the primer anvil is forced deeper into the priming mix. This places a portion of the mix over the anvil point under '"dry compression" which increases its sensitivity to the optimum level.

I had the same high primer situation. Fail the first time, fire the second time. The little plunger on my Dillon press was not pushing up quite far enough and was dragging a little on the primer feed wheel which caused a primer every now and then to now seat completely. It happens very easily on Military brass as well. Figured out the problem, stripped it down and gave it a thorough cleaning and light lube and all is good again. My fault, it had not been cleaned but once in around 50k rounds. Actually surprised it did as well as it did. I was so used to it, I didn't even notice how rough feeling it was until I got it back to new.

 

[GypsmJim]

Just a follow up.....

I received the new strain screw and installed it. The gun now runs 100%.

Looking at the old one, it looks like the old codger that owned the gun before me did some filing.

Thanks again for helping solve the problem.