double action problems with S&W mod 19-3

[Hammondbeanz]

Hi. I'm new to this forum and hope you folks can help with a problem I have with a used S&W model 19-3. When purchased, it appeared to be a "carried a-lot seldom fired piece." When fired single action it works like a S&W K frame should. When used in double action, it will have an occasional light strike on a primer and cause a failure to fire. This does not happen all the time or can happen several times with six rounds. Changing ammo and primers doesn't do any good. It also doesn't happen in the same cylinder. I took it to a local gun smith who checked it and said it just needed cleaning, which he did. This helped the problem but did not solve it. Rapid fire in double action seems to make it worse. Has anyone had anything like this happen before and what is causing this? Thanks

 

[rklessdriver]

First thing - You ned to check the mainspring strain screw. It is located on the front of the grip frame... some grips will over it so you have to remove the grips to see it. It is pointed out in this pic by the green arrow.



This is what the strain screw looks like removed from the revolver... You can see it has threads and an extended nub on the end that puts pressure on the main spring.



Sometimes the screws get are loose and back out a little.

Sometimes people grind the nub down or completely off the end of them to lighten the trigger pull.

Both instances can cause the problems your having.

If the strain screw is in unaltered condition and tight - Then you have a weak main spring or firing pin problem... but since you only have the problem in DA only it's most likely a weak main spring or the strain screw out of spec.

This is a very common thing... you would think a "gunsmith" (or at least someone calling themsevles one) would have checked these things.
Will

 

[orionengnr]

Bingo.
Find another "gunsmith"...one who knows something about S&Ws.
This is the first thing he should have looked at/for.

Edited to add: If he did, and dismissed it, my apologies.

 

[torqem]

Can't be true, cause everybody knows that revolvers are stone cold reliable and dead easy to shoot. So why would anyone do a triggerjob on one or want to lighten the trigger pull?

 

[David E]

I echo posts 2 & 3

And I encourage you to find another gunsmith. This time, find a real one.

 

[GP100man]

Bet a pepsi the screw has been ground down .

 

[BCRider]

The hammer actually travels back a little farther for a longer swing when you cock it for SA than it does in DA. So if the spring or the spring setup is marginal then it'll give more light strikes and FTF's in DA than SA.

On top of that make sure that the hammer isn't overly oiled. Too much oil will slow down the hammer just a hair. It's sort of like waving your hand underwater. It's easy if you don't go too fast but you can't wave fast. Too much oil makes the hammer act like your hand underwater vs up in the air.

For that series of dash model it has the hammer mounted firing pin. Check that the pin fits a little loose in the nose of the hammer. Also that he cleaned out any gun in the V shaped run down to the firing pin hole in the blast shield. Again it doesn't take a lot to slow the hammer down to where it gives you light strikes.

It's more about the SPEED of the firing pin than it is the actual spring power. So checking and doing what's needed to allow the hammer to reach the highest possible speed is very important. If you have the speed the firing pin will set off the primer.

All this stuff is in addition to the strain screw checks that the others mentioned. That's the first place to start.

It's also possible that some well intentioned past owner formed the mainspring to lighten the pull. If so the strain screw might be full length and tight but the spring is formed so it doesn't achieve the proper force. To check this loosen the strain screw with the grips off and check the mainspring. It should recover to a nearly flat shape. Other than the hooked end if it has anything more than about a 1/16 to 3/32 inch arch to the main part of the leaf then it's either sagged with age or was "tuned" by someone in the past. If it's bent like that then get a new one. You can TRY removing it and bending it back nearly flat. And it may work for some time. But I'd order a new one sooner instead of later.

If it's for defensive use stick with factory original. If it's a range toy only get a Wolff spring kit. Great product.

 

[VA27]

If the strain screw has been shortened a little too much, a quick fix is to loosen the screw, pick the anvil out of a spent primer and use the primer cup as a cap/shim over the ground end of the screw. If that doesn't work you'll need a new screw.

 

[chuckpro]

+1 on everything stated above. New mainspring strain screw and maybe even a new spring and you will be good to go. I am sure the spring is not wore out but if it has been ground or filed replace it with a S@W spring( wolf springs work but i think the S@W's are smother).

Does it run fine with 38's?

 

[BLU]

I've been reading up on springs for the S&W. Researched too much for my old brain to select the exact phrase or where I read it, but.... it seems you can go too light on the spring selection which will improve Single-Action performance but degrade Double-Action performance. If it were my piece, I'd purchase a new set of springs at the manufacturers specs, (inexpensive), replace them and try some range time with it. If it still doesn't work correctly, worst thing you've done is become an owner of some spare parts you'll probably use down the road anyway. IMHO it's worth a shot.

 

[Hammondbeanz]

Thanks for the help guys. I'll order a new set of springs. As far as a new gunsmith.... They're few and very far between in this part of the Southwest.