U Shaped Main Spring

[RGS]

In "Sixguns" by Keith, he mentions S&W's latest development in DA revolvers with their new U shaped main spring. He did some of the testing with it in his revolvers and said they never had a better DA pull than with that new main spring installed. He called it a large step forward in DA design. He liked them better than the old long action triggers, and better than the new short action triggers.

So the question is. Where are the U shaped main springs?? Why were they dropped??

I've never heard of such a thing, but according to Elmer Keith, they were standard equipment starting about 1960 or so in the M1950 Target. Did they ever put it into the S frame guns?

 

[M29since14]

Those guns would have been S- serial numbered N-frames, so to answer your question - yes. Generally, I thought the spring was referred to as a "W" mainspring, rather than "U." I hope we're talking about the same thing.

Unlike Keith, I could never tell much difference, so I could never see much advantage. The good thing is all of the frames I have seen of guns so equipped were also drilled and tapped for the strain screw, and notched for the standard mainspring, so if you broke a spring and wanted to replace it with a normal mainspring, you could.

 

[Muley Gil]

There were two types of "other" mainsprings-the "U" and the "W". Both replaced the rebound spring. Both tended to weaken with use and the company went back to the standard flat mainspring and the coil return spring.

Somewhere in my parts stash, I have one of each. IIRC, the "U" and the "W" were installed in 1955 .45 revolvers when first introduced.

 

[Nightowl]

I seem to remember they started having light strikes and were unreliable, so the change back to the standard main spring.

 

[H. M. Pope]

I've used both the U and W mainspring for many years of target shooting at Camp Perry and other events.

Never had a problem with them, However some times if you were using re-loads and your primers were not seated to the bottom of the pocket you would get misfires. I think they got a bad rep because of that.

For thjose that have never seen them here's some photos.
H. M. Pope

 

[Doc44]

Dwayne Charron, whose book, "My Life Journey with Smith & Wesson" has recently been published, played a key role in the development of the "alphabet" main springs (U and W shaped). He comments the misfires were a result of shooters using military surplus ammunition with hard primers.

I have a 1955 Target 45 with a W main spring that I have shot successfully (without misfires) for many years.

Bill

 

[M29since14]

I have a 1955 Target 45 with a W main spring that I have shot successfully (without misfires) for many years.
Bill

I too have a 1955 (mine in the S165xxx range) with the W-mainspring. It only gets my handloads and I too cannot remember ever having any misfires/light-strikes. The trigger does seem a little lighter than a similar modern gun I have (late 70s model), but I shoot them both about the same. A better shot might prefer one or the other.

 

[Muley Gil]

"For thjose that have never seen them here's some photos.
H. M. Pope"

Thanks for posting the pics. Now I don't have to dig through my parts and take photos.

 

[Homie]

Dwayne Charron, whose book, "My Life Journey with Smith & Wesson" has recently been published, played a key role in the development of the "alphabet" main springs (U and W shaped). He comments the misfires were a result of shooters using military surplus ammunition with hard primers.

I have a 1955 Target 45 with a W main spring that I have shot successfully (without misfires) for many years.

Bill

Bill,
Do you have a source for the book- I can't find it anywhere? Thanks.

FWIW, I've got my 5-screw "family" .357 with a "U" spring that's been 100% for 57 years!

Good shooting.

 

[RGS]

This is interesting. It seems to me just reading these responses, the U and W shaped main springs may have been brought out ahead of their time. If soft strikes were had with the primers of the day, today's choices would certainly relieve that issue.

These new main springs simplified and improved the product. The whole trigger return mechanism could be removed. The main spring would handle and balance trigger pull and trigger return perfectly. This one change so simplified and improved the factory product, I wonder why it was so short lived? And why with today's primer selection, it isn't offered again?

I suspect this U shaped main spring also effected the single action trigger pull. Seeing as most DA revolvers are used in SA mode most of the time, I think most buyers of the S&W product, for whatever reason, didn't want and wouldn't buy the new design. Sales is the name of the game, so S&W gave buyers what they wanted, and what they were willing to pay for.

Too bad Wolff doesn't offer something like this. I shoot DA most of the time. I'd have liked to had the option of trying this design.

 

[Muley Gil]

"The whole trigger return mechanism could be removed."

No, all the U and W mainsprings replaced was the rebound spring that is housed inside of the rebound slide. One end hooks on the hammer and the other end bears against the rear of the rebound slide.

 

[Wiregrassguy]

Homie,
His website is Index. AFAIK, he is still signing the first 500 copies so chances are good you can get an early signed version.

 

[jaymoore]

I had a intriguing old Spanish 32-20 revolver that had a "U" mainspring which also ran the trigger return. Probably 1920s or '30s vintage. Several nice design features, but the usual questionable execution. (It had a Dan Wesson-like cylinder release, but that's irrelevant for this thread.) It might still be available for photos, though.

I wonder if S&W might have copied the Spanish knock-off in this instance?

 

[Homie]

Homie,
His website is Index. AFAIK, he is still signing the first 500 copies so chances are good you can get an early signed version.

Guy,
Thanks for the link. Looking forward to some interesting reading!

Good shooting.

 

[kdailey]

Everyone should get a copy of Mr. Charron's book. His personal story of the many years with S&W are incredible.

 

[son-of-a-gun-designer]

Bill,
Do you have a source for the book- I can't find it anywhere? Thanks.

FWIW, I've got my 5-screw "family" .357 with a "U" spring that's been 100% for 57 years!

Good shooting.

Hello!

My name is Dean Charron and I am Dwayne Charron's son and publisher. The Smith and Wesson Forum will be doing a mass mailing in a couple days specifically for my dad's book. There is also a link in this weeks S&W Forum newsletter to the books website, which is Click Here. My dad did a section in his book about this spring and I own one of the few known guns with the experimental spring in it.

Best,

Dean
[email protected]

 

[son-of-a-gun-designer]

Homie,
His website is Index. AFAIK, he is still signing the first 500 copies so chances are good you can get an early signed version.

Just thought I'd jump in and let you know that we are still issuing books numbered and signed by my father Dwayne. The Smith & Wesson Forum is doing an exclusive emailing for my dad's book in a few days so I don't think the signed and numbered books are going to last too long...

You can get his book here: My Life Journey with Smith & Wesson.

Best,

Dean Charron

 

[son-of-a-gun-designer]

Everyone should get a copy of Mr. Charron's book. His personal story of the many years with S&W are incredible.

Keith,

Thank you so much for your kind words, which made my father's day. My dad is now 87 and didn't want to let his knowledge and experience be lost so he worked hard to get this book done for posterity.

Best,

Dean Charron

 

[Homie]

Gents,
Received mine yesterday- it's a must for everyone that wants to know "the rest of the story".
Thank you Dwayne!
Good shooting.

 

[sceva]

Just thought I'd jump in and let you know that we are still issuing books numbered and signed by my father Dwayne. The Smith & Wesson Forum is doing an exclusive emailing for my dad's book in a few days so I don't think the signed and numbered books are going to last too long...

You can get his book here: My Life Journey with Smith & Wesson.

Best,

Dean Charron

Just ordered one - I hope it comes signed