Revolver mainsprings......

[Harry O]

I have owned many, many revolvers through the years and have changed the mainspring (hammer spring) on many of them. Always lighter. I usually change if the mainspring is heavy enough that it interferes with my accuracy. This is what I have noticed.

1. My older S&W’s (from the 1920’s through the 1960’s in both centerfire and rimfire) do not need a mainspring change, in my opinion.
2. The S&W’s I have from the 1980’s or newer have much heavier mainsprings (J, K, and L frame). I have lightened the centerfire ones (usually .32, .38, or .357) with aftermarket springs (leaf and coil). I have not had any problem with any of them failing to ignite the primer. I don’t have any newer rimfires, so I don’t know if they have heavier mainsprings (but I am guessing they do) or if there would be a problem with ignition.
3. I have only a few Colt’s, mostly old (1930’s to 1950’s), and have not had to change the mainsprings with them.
4. All the Ruger’s I have (SA and DA) really, really need lighter springs. The DA ones are the worst. They usually come in a 3-spring pack. I have had several problems with occasional failures to fire with the lightest spring. The middle spring does not have an ignition problem with my loads. It is a big improvement, but the trigger pull is still not as good as a S&W or original Colt. Remember to clean up the trigger return box for its spring before reassembly (DA ones) whether you use the original spring or not. Ruger single-actions don’t have as many choices and have not been any problem.
5. The springs for the Uberti single-actions are easy to change and have not been any problem at all. The most important thing to change is the trigger/bolt return spring. Use a wire one, not a leaf one.
6. Several other miscellaneous revolvers I have could use a mainspring change, but I have not been able to find a replacement for them. H&R’s and Charter Arms are a couple of examples. The Charter Arms revolver has one of the heaviest mainsprings of any gun I own. I may someday get around to shortening the spring with a grinder (or thinning it; I have not taken it apart to see), but I have hesitated, because of a failure in doing that on a different gun many years ago. It was very difficult to get a replacement stock mainspring back then (this was in the pre-Internet and pre-warehouses for gun parts days).
7. Sometimes I also change the trigger return spring in DA's along with the mainspring (they often come as a package), but not too often. If the stock trigger return spring is very strong, I may change it. If it is not too strong, I leave it alone (try it without the mainspring attached). One time I changed it on a Ruger and it was too weak. Failure for the trigger to return quickly really messes up shooting.

Does anybody have any other experiences to add?

[Tatume]

Changing the rebound spring is a good way to improve trigger pull in S&W revolvers. They usually come in 13, 14, & 15 pound strengths. First remove the rebound slide and polish the two bearing surfaces on a flat, fine whetstone. Install the 13 pound spring and try it, if the trigger fails to reset with authority, try 14 pounds, etc. I like to lubricate most surfaces with a mixture of gun oil and STP on final assembly. The trigger-hammer surfaces get molybdenum grease.

[Drm50]

On main springs in K & N frame S&Ws, I have seen aftermarket main springs that are so light that
it results in ununiform ignition from light striking. You would be surprise how that affects accuracy.
Also results in misfires. Have also seen guys that tune up factory main by thinning it. That doesn't
work out well either. Spring will usually break in a short time when the load on it is not as designed.

[Char-Gar]

The only thing I might add, is the older Smith and Colt revolvers mainsprings, often appear to be lighter because they loose strengh with use. On the same note installing lighter mainsprings often are just pre-worn in their feel. With use, factory springs will lighten and action will smooth out.

[William Yanda]

Not to hijack, but the OP mentioned Uberti. Anyone have experience with Pietta?

[Harry O]

I have a PPC revolver made by Bill Davis about 40 years ago. The double action trigger pull on that one is lighter than the DA trigger pull on every other revolver I have ever owned. It is even lighter than the single action trigger pull on some of my other revolvers.

It would not ignite anything (reliably) other than light handloads with firmly seated soft Federal primers. I kept it that way for many years and it did not appear to change. Like you, I expected it to fatigue and start to fail to ignite the Federal primers, but that never happened.

I have no doubt that some aftermarket springs might take a set eventually and lose power. However, that has never happened with my Wolff or Wilson aftermarket springs. I doubt that that happens with S&W factory springs either.

PS: I only own one Pietta, a single action percussion revolver, and it does not need to have the spring changed.

[Xringshooter]

Harry O, when I was shooting PPC, we would always go with Federal primers because they were the softest and provided reliable ignition with the light mainsprings.

I actually built a PPC gun from a Ruger GP100 (a Ron Power bull barrel and Bomar (IIRC)rib sight with a 4 position rear sight I got from Brownells (this was 1990-1992). Sold it to a friend (never should have it was a great shooter) when I was selected to go to Egypt as part of a special team to help get the Egyptian AF get up and running with F-16's.

I ran a 9 lb mainspring and a 8 lb trigger return spring and polished the top of the mainspring strut, hammer dog, sear and trigger. It was smooth and light and shot great. I got a lot of complements from long time S&W gunned PPC shooters. At that time our load was .38 spl case, 148gr HBWC, Federal 100 Small Pistol primers and 2.5 grs of Red Dot. Dirty but shot great.

Before I start changing springs, I'll clean everything up, remove any burrs, polish and touch of grease on the bearing surfaces, shim if need be and see how it shoots. Then, if not happy with the trigger pull, I'll start swapping springs until I get something I like and reliably ignites the primers I'm using.

[Petrol & Powder]

I've been playing this game for many years and spring weights are a double edged sword.

People have a tendency to equate light DA pulls with accuracy and that's not absolutely true.

A heavy DA pull that disrupts your hold may interfere with your hold and therefore your accuracy. However, a lighter mainspring that increases lock time may negate any advantage earned from that lighter pull.
Like every thing else, there's compromise involved.

Ruger DA revolvers have the most room for improvement. Ruger compensates for poor internal finishing with heavy springs, in fact VERY heavy springs. The geometry of the Ruger lockwork is also different from a S&W . Some careful polishing of the Ruger action, coupled with shims and maybe reduced springs - yields dramatic improvement.

The S&W actions are closer to where they need to be to start with. They can benefit from action work, including springs on occasion just as well but there's less room for improvement.

As for trigger return springs, I do a lot of DA work and often prefer to keep the original springs in place to assure a positive trigger return.
That practice probably doesn't allow for the lightest possible DA pull but that's the price you pay for a fast and positive trigger return. It's that compromise thing again.

THEN, we have the lock time problem. If you get too light on the mainspring you will increase lock time and that works against achieving the best accuracy. Light trigger pulls aren't necessarily and good thing.

I also agree with Char-Gar, an old, well used revolver may have a better trigger pull party due to weaker old springs.

I generally like to keep things close to original unless they are just unacceptable. As much as I love Ruger's, you could use some of their springs for truck suspensions.

[Andyd]

Doing a good trigger job involves a little bit more than a simple spring swap, the power that the rebound slide needs to reset the trigger has to be greater than the friction it is working against; so polished contact points will help with a positive reset while using a lighter rebound slide spring. The main spring in contemporary S&W revolvers is a little on the heavy side, too, but this is to ensure positive ignition. On my competition bowling pin revolver I had the main spring tweaked to work with Remington primers, which are softer than Wolf or CCI primers.



On a Korth the rebound spring can be adjusted from the outside.