Light strikes - Model 10

[rajbcpa]

This revolver was in pristine condition - never shot when I bought it from a private party earlier this year. I believe the circa is around mid-1990s with factory rubber grips and a 4 inch barrel.

Anyway, about every 7 or 8 rounds it fails to fire (FTF) which results from a light primer strike.... If I recycle the un-fired but previously struck ammo it goes bang so it is not an ammo issue... This happens when it is fired from the double action mode...

I thought this was a result of a dirty gun but I cleaned it well and it FTF at the range every time it is shot.

The ammo is reloaded but the primers are seated correctly and these rounds fire every time in other S&W revolvers.

Any ideas on how to solve this?

Thx...

 

[H Richard]

Have you checked the Strain Screw against the mainspring? It could be backed out a bit, (what uneducated people do to lighten the trigger pull). Or, it might have a lower power spring installed.
That vintage revolver normally didn't have any "short pin" problems. How does the action feel? Is it a light trigger pull? Does it feel like it has had a trigger job done? How do the firing pin indents in the fired primers look, normal or light hit?

 

[rajbcpa]

...ammo that fails to fire has a light primer strike and the action feels light on these strikes when [after] the trigger is pulled.

The firing pin looks normal and the gun has been well oiled.... I suspect it is a spring issue. ???

 

[H Richard]

It sounds like a mainspring issue, either backed out strain screw, or lightened spring. Take the grips off and see, and tighten up the strain screw as much as it will go. It could be a previous owner shortened the strain screw, that can be easily replaced. If you think the screw has been shortened you can put a fired primer cup (remove the anvil) over the tip of the screw and increase the length, or other shims can do the same thing.

 

[Double-O-Dave]

H Richard is correct - in my experience, I've seen quite a few K-frames with altered mainsprings and backed-out, or shortened strain screws that were attempts at lightening the trigger pull - never a good idea. If H Richard's suggestions regarding the strain screw don't work, I'd suspect the mainspring is the issue. Also, without photos it's hard for me to say, but I don't think rubber grips were factory issue for your Model 10. Photos would help.

Good luck,

Dave

 

[Pisgah]

You do need to check that the strain screw is tight. But in spite of your assertions to the contrary, odds are about 90 per cent that your primers are not properly seated. I know, I know -- you, and your reloads are perfect. Me and mine, too. Still, it'll be worthwhile to give those primers a little nudge.

 

[H Richard]

Pisgah has a good point, especially if you didn't personally load that ammo. If primer not seated all the way, the first hit moves the primer forward into the full seating depth, and the second strike sets it off.

 

[rajbcpa]

....ok, - me too, the first time at the range, I thought it might be high primers also.

...but after about 2,000 rounds of this reloaded ammo, the FTFs only occur in the Model 10 and not at all in the other 3 Smiths.... ...and the FTFs occur every 6 or 7 shots time and again with this gun only...

 

[scooter123]

Since you haven't responded to any of the suggestions to check the Strain Screw I can only conclude that you don't know where it is or what it does.

The Strain Screw is a screw in the lower front strap of the grip frame that applies tension to the Main Spring. When this critical screw works loose or is improperly fitted the result is a reduction in the DA Trigger Weight and when too much tension is lost in the Main Spring you get issues with misfires.

It's why almost every reply has stated you need to check the Strain Screw. Because most of us have been on this particular Rodeo Ride and we've learned first hand what happens when the Strain Screw isn't applying the correct amount of tension to the Main Spring.

 

[Alk8944]

rajbcpa,

Usually I wouldn't comment after so many responses, especially correct ones. First, read my sig. line then listen. More than 90% of the time a revolver is giving light strikes is because the strain screw has been loosened, either deliberately or from vibration from shooting it. Most of the rest of the time the strain screw has been modified.

Contrary to some comments, a primer that is not fully seated will not give a failure to fire if the mainspring tension is at factory level! In most cases, if a primer is not fully seated, to the point where this would be an issue with a revolver, the cartridge will not allow the gun to close or the primers will drag hard enough on the breech as to cause functioning problems! If the gun will close, and the cylinder turn freely, the primers are adequately seated and will not cause an ignition problem! It's time this myth be put to rest!

 

[rajbcpa]

....I checked the spring tension screw and it was tight. I removed the screw and it has not been filed down since there are small machine groves in the screw where it meets the spring.

I reassembled the gun after applying a light coat of gun oil to the internals.

I need to get the gun back to the range to check it again.

 

[brick]

I have the same problem at times. My problem is due to using CCI primers. It does not happen with Remington or Winchester primers.

 

[growr]

Alk8944 is right on in his comments on high primer condition.

The only handgun that this IS an issue, is with a cap and ball revolver when using caps that don't fit the nipples properly.

Yours is not a cap and ball revolver however.......

Randy

 

[federali]

Actually, shortening the strain screw is the correct way to lighten the trigger pull but only if the double action pull exceeds factory specs of 12 pounds. As with any "gunsmithing," get too happy with the files and stones and you're left with expensive scrap metal.
As others have said, loosening the strain screw should never be done.

It should also be noted that a really bad flinch (not limp-wristing) can soften the hammer fall enough to cause an occasional FTF

 

[crankyoldlady]

Does this happen in single action?

When shooting double action do you "stage" the trigger or squeeze straight back in one fluid motion?

 

[rwsmith]

It's not the primers...

I have the same problem at times. My problem is due to using CCI primers. It does not happen with Remington or Winchester primers.

A model 10 should be able to fire any primer. I've mostly used CCIs as well as Remingtons, Winchesters and maybe some Federals. My model 10 never failed to fire unless I had done something wrong. The hammer on the OPs gun isn't hitting the primers correctly.

 

[rajbcpa]

I took the gun back to the range today. Unfortunately, it still fails to fire about 1 time in 10. The reloaded ammo works fine in all three other Smith revolvers....

I suppose I will take it to a gunsmith.