Rebound spring- Picture added
 

I recently bought a 38 Masterpiece (at a decent price) from about 1948. I bought it as a project gun and a learning tool. I have Kuhnhausen's manual, as well as a couple others for reference. that I've spent several hours reading and analyzing.

It would fail to fire one cylinder fairly consistently. I took it apart, and found a number of "questionable" smithing problems (which may have been how they did things way back when):

1. Mainspring was weakened by bending (which I was pretty sure was causing the misfires).

2. Strain screw was shortened (which didn't help anything).

3. Rebound spring cut to 12 coils-about 3/8-1/2" shorter than stock.

3. Hand filed flat across the top-2 chambers were out of time and would not lock up).

Taking one thing at a time, a new mainspring and strain screw solved the failure to fire problem, but the trigger would not reset consistently (not surprised because of the too short rebound spring).

I had a 15lb spring from a Wolff kit, so I put it in, and could not cock the hammer, either SA or DA. I have a few stock S&W rebound springs around, and none of them will allow cocking the hammer. Since I had a few laying around, I cut 2 coils of of one, and it works, but the trigger pull is a little strong. But like I said, one thing at a time. I can deal with the stiff pull if it's smooth. I'd rather have stiff and reliable than light and unreliable.

So, my question is why won't it cock with a stock S&W rebound spring? It has to be either the rebound slide or trigger lever than actually pushes the rebound slide. Is it possible the trigger lever was replaced with a longer one to compensate for the too-short spring?

Once I get this stuff figured out and corrected, I'll deal with the hand being all wrong.

Thanks, Bill

If someone cut the rebound spring as short as you say it would basically fall into the gun with no compression. If the gun was functioning with a spring that short there has to be a spacer in the rebound slide to give it some compression. If you installed a standard spring with he spacer in place I would expect that the gun could not be cocked because the spring would coil-bind and prevent full travel of the rebound slide. Some way you have to get the spacer out of the rebound slide.

Depending on how a spacer was installed, and what it is made of, it may be difficult to remove. You may have to drill it out.

The hand should have a slight flat on the end. S&Ws do not lock on the end of the hand like Colts, they depend on the thickness of the hand. When close to full carry-up the hand bypasses the ratchet lug and bears on the side of the lug. The failure to carry-up can be repaired with a new oversize (thicker) hand, slightly peening the ratchet lugs to spread them slightly, or slightly bending the hand. Unless you really understand the S&W lockwork, and obviously you do not, none of these fixes are something you should attempt as you can do a lot of damage really quickly. David Chicoine www.oldwestgunsmith.com would be a good place to start. There are very few gunsmiths that can be trusted to repair either S&W or Colt double-action revolvers, unfortunately.

A good place to start would be to buy a copy of Jerry Kuhnhausen's "The Smith & Wesson Revolver, a Shop Manual". You can buy it from many on-line booksellers, Midway, Brownell's, etc.

I thought about a spacer of some sort but can't see anything obvious in the rebound slide. The gun functions, but does have an occasional failure to reset (not anything consistent.)

Do you know the depth of the rebound slide? I think my next step is a new one.

Thanks for the advice.

Is this failure to reset in double action allowing the cylinder to rotate on the next trigger pull but NOT cocking the hammer? If so, you need to chamfer the tip of the DA Sear on the hammer a bit more. It's part of the process of fitting a new hammer assembly and may have been skipped by whoever was "smithing" on your gun before you acquired it. Attached is a pic of the chamfer and angle on the hammer assembly that was installed in my 625 JM, so it's an untouched factory part.

BTW, I wanted a smooth .400 trigger in my 625 JM so I replaced both hammer and trigger with blued parts. That is where I learned this chamfer is essential and what happens when the sear is left sharp.

[QUOTE=scooter123;136400626]Is this failure to reset in double action allowing the cylinder to rotate on the next trigger pull but NOT cocking the hammer? If so, you need to chamfer the tip of the DA Sear on the hammer a bit more. It's part of the process of fitting a new hammer assembly and may have been skipped by whoever was "smithing" on your gun before you acquired it. Attached is a pic of the chamfer and angle on the hammer assembly that was installed in my 625 JM, so it's an untouched factory part.

This is called the "short cut" on the sear by S&W.

Hope this helps
chris

I have a rebound slide in my parts box that won't take a full length spring without coil binding.

I checked mine, and no broken parts or spring pieces stuck in there, it was just drilled that length.

WildBillD,

You asked how deep the hole in the rebound slide is. I just measured two, a 1961 +/- K-32, and a 1947+/- K-38. The hole in both was drilled with a standard drill bit with a tapered point, it is not flat bottomed.

To the point where the 1/8" diameter rod of my depth micrometer contacts the tapered bottom of the hole the K-32 measures .885", and the K-38 .898" Hope this is helpful. If yours is significantly shorter than .875, or appears flat bottomed, that would be a very good indication that there is a spacer in the hole. Drilling it to the proper depth, with a drill of the right diameter, would be the easiest way to handle this.

This is a very good example of the basic fact that contrary to popular belief everyone with a kitchen table, screwdriver and hammer isn't a gunsmith! Although someone obviously thought he was.

And, for M1gunner, just because you have a rebound slide with a shallow hole doesn't mean this situation is in any way normal. All it means is you have a defective part which probably has never been installed in a revolver. This is not at all uncommon.

Mine is obviously used and came from a M-19

First of all, thanks for the replies and advice.

Scooter and Chris: When it fails to reset, the cylinder does not rotate and I have not tried pulling the trigger again. The chamfer on the sear is not sharp, but rounded off. Likely the problem.


Alk8944: The rebound slide hole is not flat bottomed and does not appear to have been modified that I can tell. No spacer, but I measured it at .825", substantially less than yours. Also, a picture of the rebound spring I took out (on left), and a stock spring from a 686. The stock spring measures roughly 1.16", the original 0.85":

http://i319.photobucket.com/albums/m...6/DSCN0054.jpg

I do have Kuhnhausen's manual and Sweeney's gunsmithing pistols. I know there a lot of "variations" on parts, and have seen several S&W revolvers with different trigger pulls. Some good, some not so good. Buddy of mine has a Model 10 that has the worst trigger pull I've ever seen, and gun is totally untouched. Another guy I know has a Model 15 that has never been touched and has an excellent trigger.

I'm thinking this thing was not good from the factory, so someone did what they could to try to make it better. It may have worked, but certainly was the the right way to go about it.

Thanks again for the help.

Hi ;)

I was wondering... You got some other S&W. Why don't you pick a rebound slide in one of them and try it in this wheelgun just to see what' happening ?