[joshk-k]

My friend showed me an old S&W .38 special that belonged to his grandfather last night. Some time about 20 years ago, my friend, while cleaning it or something, removed the wood grips from the frame and did something to the spring that runs from the base of the handle up to the hammer. Now the hammer will not stay cocked to the rear. You can fire the gun in DA, but when you pull the hammer back manually, it just springs forward.

What can he do to fix this problem?

Thanks,
Josh

[Sunray]

He likely took it apart and reassembled it incorrectly. Start by taking it apart and reassembling it properly.

[joshk-k]

Could you point me to a diagram of what it would properly look like or instructions for proper reassembly, please?

THanks,
Josh

[BCCL]

The spring is not the problem, or it would not work DA either.

He either damaged the SA sear or left a part out during reassembly.

[BCCL]

Could you point me to a diagram of what it would properly look like or instructions for proper reassembly, please?

http://www.snubnose.info/docs/lockwork.htm

http://www.snubnose.info/images/Parts_chart_640.jpg

His gun may have a flat spring instead of the coil one shown here.

[joshk-k]

Beautiful! Thank you!

Josh

[Oro]

Um, that diagram above is for a J frame .38 only. Based on what the OP said:

the spring that runs from the base of the handle up to the hammer.

This describes the K frame, where the spring is indeed in the base of the grip frame, not part of the way up. If you have an M&P (k frame), see the well-done "S&W model 10" instructions stickied at the top of this forum. The K frame has a different mainspring (leaf, not coiled) than the J. A loose (or filed/shortened) mainspring screw is frequently what causes the condition you described.

[BCCL]

Wow, great thread on the M10, ignore my picture, the ones there are much better!!!

[joshk-k]

Thanks for the info!

Josh

[krs]

Follow the arrow marked "SA Sear".

See how the R/H surface is notched - a very small rise or blip toward the right side of the photo? That's the single action sear engagement surface on the hammer.

If your friend 'smoothed the action and inadvertently rounded off that tiny edge the pistol will not cock for single action shooting.

All due respect to Oro, but I'd think that shortening the hammer spring tension screw too much would cause light primer strikes but still allow for single action cocking.

Rounding off the SA sear surface on the hammer is not an uncommon error in 'home gunsmithing' of these revolvers. Unfortunately the fix is a new hammer.

[Oro]

All due respect to Oro, but I'd think that shortening the hammer spring tension screw too much would cause light primer strikes but still allow for single action cocking.


You are correct. It will cause the hammer to "short stroke" like he described in DA, but not SA. I was not thinking of all the dimensions of the problem as he described it.

It sounds to me like the hammer was inserted without the trigger being partially the retracted.

[joshk-k]

Well, an update. When he first took it apart, 20 years ago, he said he only removed the grips and didn't get into the real workings. I ended up just monkeying around with the hammer spring tension screw and got it to work. Now you can cock the hammer back and have it stay there.

But now there's a new problem: When you pull the trigger in SA mode, the trigger does not stay to the rear. Upon being pulled, it leaps forward, and it's not clear whether the hammer is getting a good strike. Is the hand supposed to hold the trigger in place after the SA sear has disengaged from the sear engagement hook?

Thanks for all the help so far, and I hope you can help me with this one too.

Yours,
Josh

[BCCL]

Please don't take this in a bad way, since I don't know how much experience you have with gunsmithing, but it's starting to sound like that gun needs to be checked by one, or sent to Smith & Wesson to be checked.

[joshk-k]

I don't take it the bad way at all! I have no gunsmithing experience. I am somewhat mechanically inclined and also have a strong "DIY" attitude, which is why I'm even giving this a gander. He did this to the gun twenty years ago and hasn't shot it since, so he knows full well that he may need to have it professionally worked on anyway.

Thanks though.

JOsh

[.41Dave]

But now there's a new problem: When you pull the trigger in SA mode, the trigger does not stay to the rear. Upon being pulled, it leaps forward, and it's not clear whether the hammer is getting a good strike. Is the hand supposed to hold the trigger in place after the SA sear has disengaged from the sear engagement hook?

If I understand correctly, you are saying that when the trigger is pulled after cocking the hammer, the hammer falls and the trigger automatically returns to the forward position unless held back by the trigger finger, yes? If so, that is exactly what is supposed to happen. The rebound spring (see diagram posted by BCCL) exists for the sole purpose of resetting the trigger to the forward position in preparation for the next shot. If the trigger remains in the rearward (fired) position after being released by the trigger finger, it means something is very wrong.

[joshk-k]

"If I understand correctly, you are saying that when the trigger is pulled after cocking the hammer, the hammer falls and the trigger automatically returns to the forward position unless held back by the trigger finger, yes?"

Almost. When the trigger is pulled, it returns forward with such speed and force that you can't hold it rearward with your finger.

JOsh

[Jim K]

The first problem was probably that when the strain screw was turned out, the mainspring tip butted against the bottom of the hammer. That will prevent the hammer from coming back far enough to cock in SA mode.

Now the problem with the trigger going forward COULD be the same thing. Make sure the strain screw is fully in and the end of the spring does not touch the hammer except at the stirrup (the part the spring hooks onto).

If all is well and the condition persists, the hammer and/or the trigger (sear is part of the trigger) may have to be replaced.

Jim

[ArchAngelCD]

And it sounds like you have the strain screw cranked down REALLY tight. Back it off before you break something else.

[.41Dave]

Josh, the only thing in the revolver capable of returning the trigger to the forward position is the rebound spring. The factory strength of this spring is 18 pounds. A person with normal grip strength should be able to hold the trigger back against the force of the spring. Are you sure it isn't just surprising you when the trigger breaks, causing you to release pressure? If the force of this spring is such that it cannot be overcome with finger pressure from someone with normal grip strength, then this is a problem I have never heard of or encountered in many years of collecting S&W revolvers.

You could try replacing the rebound spring, perhaps with a reduced power spring such as is available from Wolff, but I do not recommend that unless you know how to disassemble and reassemble an S&W without damaging the sideplate. Removing the rebound spring is also rather tricky unless you have a special tool or a screwdriver specially modified for the task. Taking the revolver to a gunsmith may be your best bet.

[Drail]

What you are describing is the classic "hammer hits trigger" problem. The problem is the single action sear is not interfacing correctly with the trigger. The hammer or the trigger have been swapped or altered. This is a qualified S&W or smith repair.