Can springs effect accuracy?

[Thumbcocker]

Mrs. Thumbcocker and I acquired a Smith 15-3. The previous owner had put aftermarket springs in it. Accuracy was nothing to write home about and we had several failures to fire. Fortunately the seller included the factory springs. With the original springs installed no misfires occurred and it seemed to both of us that the accuracy was much better.

My question is did putting the original springs back in make a difference in accuracy or did we just do better with more trigger time and no annoying misfires? I have haerd that consistent hammer strikes can result in more consistent ignition and thus better accuracy but don't really know.

[charlie b]

... no annoying misfires...

I suspect this is why. If I have a pistol that misfires I lose my concentration just a bit.



Sent from my SM-P580 using Tapatalk

[onelight]

I read somewhere in the last 65 years :veryconfu that it can and will cause vertical strings, but I have not tested it. It would be interesting to shoot groups with a smith while backing out the strain screw to see if it does. One might need a scope a bench and sand bags to see if it is true.

[str8wal]

One might suppose that longer lock time with the lighter springs could require more consistent follow through and if your trigger control isn't 100% it might affect accuracy. Just throwing that out there.

[Der Gebirgsjager]

Sure, accuracy can be effected. Factory springs tend to be stronger than aftermarket springs, as the revolver owners are looking for lighter, smoother actions. Consistent mechanical performance from shot to shot is what they seek, and of course consistent ignition is very important, so we'll take that as a given requirement of any action job, as a gun is supposed to fire reliably when the trigger is pulled. The results of having the factory or replacement springs depend a lot on the shooter's technique and ability. Most beginning revolver shooters use stock equipment, and very often with good results. Most revolvers are best left that way, but if the shooter shoots a lot he may begin to feel that if the trigger required less effort to pull or the hammer dropped more quickly his scores would improve, and these require some custom work. The balance is to achieve smoothness with reliability. Back when revolvers were the standard equipment in law enforcement many departments forbid any alteration of
the issued weapons solely because of reliability issues. Many shooters do quite well with factory spec revolvers and replacing the springs can cause problems. My opinion: If you're new to revolvers you want stock equipment. If you're an advanced competitive revolver shooter you will probably want an action job that will include replacement of the springs, but make sure that a real expert does the work, and even their jobs sometimes go bad with extensive use.

DG

[tazman]

Sometimes light hammer springs can cause inconsistent ignition if the primers are not being struck hard enough. This would affect accuracy.

[M-Tecs]

I can't address how much weak spring effects revolver accuracy since I have never tested them. I do have first hand experience with rifles. Worst I have seen was a 1/2 MOA match rifle turned to 2 1/2 to 3 MOA rifle due to spring issues.

[Thumbcocker]

I read an article by Ross Seifried many years ago where he advocated stronger than factory mainspring in Ruger single actions for his big cartridges. He wanted primers to get a good smack.

I never change mainspring in my single actions but will put in slightly weaker trigger return springs and buff all the engagement surfaces with a cloth wheel and polishing compound on a dremel tool.

[Petrol & Powder]

I think on a DA revolver there is more than one factor at play when talking about the mainspring (hammer spring).

Reducing the strength of the mainspring increases lock time which could decrease accuracy.
However, reducing the effort required to fire the gun in DA might potentially improves the shooters ability to release the hammer without disturbing the sights.
It comes down to where is the barrel pointed when the hammer is released and is the barrel still pointed in that same place when the bullet exits the barrel.

A shooter that is able to cycle a DA trigger without disturbing the sights will likely benefit more from a shorter lock time (stronger hammer spring) and a shooter that has difficulty maintaining sight alignment during the DA pull might benefit more from a lighter DA pull weight (weaker hammer spring).

If you were to plot those two functions (lock time and the shooters ability to maintain sight alignment) on a graph you would get two sloping lines that intersected somewhere at an optimum point. Too heavy of a mainspring and it becomes difficult to maintain sight alignment (accuracy suffers); too light of a mainspring and lock time becomes excessive (accuracy suffers).
Somewhere in the middle of those two factors is a sweet spot where a particular shooter will get the best results.

NOW, it's better to improve your hand strength and skill with a DA revolver than it is to compensate for weak hands and poor technique with lighter springs.

I think it is desirable to improve the action of a DA revolver by making the action smoother but not necessarily lighter.
Reducing the power of the mainspring has another negative consequence besides longer lock time and that is unreliable ignition. So in addition to increasing the lock time, a weaker mainspring ALSO reduces reliability at some point. I don't care how wonderfully light a DA trigger pull is, if it doesn't go bang 100% of the time - it's too light.

In a perfect world, the shooter would be able to cycle a DA action without disturbing the sights AND have the shortest possible lock time.

Most DA revolvers in their factory, unaltered configuration will be 100% reliable and have reasonable DA pull weights. So for those I think leaving them alone is the way to go.
The noted exception to that practice may be the DA Rugers. The Ruger GP-100 and the Ruger SP101 seem to suffer from less than perfect internal finishing AND excessively heavy factory springs. They respond very well to cleaning up the actions and reducing the weight of the mainsprings a little bit. If the action is polished a bit the mainstream can be reduced by a couple of pounds while maintaining 100% reliability.

[country gent]

Springs can and do affect accuracy in several ways. 1) lock time heavier springs give a faster lock time 2) better ignition of the primer, a light hit may not fully ignite it instantly like a full power hit does. 4) I believe the springs and resulting hammer fall have a bearing on the harmonics of the firearm. These start from the pull if the trigger to when the bullet leaves the barrel.

One of the popular mods on garand and M14/M1A triggers was to mill one side of the hammer away and install a heavier hammer spring. Then you did the trigger job. This greatly sped up lock time, Gave consistant hammer hits, and worked well. The lightened hammer heavy spring made offhand easier.

[6string]

Doug Wesson tested exactly this using the "new" 357 magnum 245983
Using the machine rest at the S&W factory, he showed the effect of reducing mainspring tension on accuracy. The results were remarkable! At 20 yds, six shots clover leafed into one tidy hole when the spring was at full tension. When reduced, the group opened up to greater than twice the size.
This was in the 1930s. Not sure how much changes in primer formulation would affect results today.
Jim

[Texas by God]

Doug Wesson tested exactly this using the "new" 357 magnum 245983
Using the machine rest at the S&W factory, he showed the effect of reducing mainspring tension on accuracy. The results were remarkable! At 20 yds, six shots clover leafed into one tidy hole when the spring was at full tension. When reduced, the group opened up to greater than twice the size.
This was in the 1930s. Not sure how much changes in primer formulation would affect results today.
JimAnd there it is. Thanks 6string.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[M-Tecs]

Doug Wesson tested exactly this using the "new" 357 magnum 245983
Using the machine rest at the S&W factory, he showed the effect of reducing mainspring tension on accuracy. The results were remarkable! At 20 yds, six shots clover leafed into one tidy hole when the spring was at full tension. When reduced, the group opened up to greater than twice the size.
This was in the 1930s. Not sure how much changes in primer formulation would affect results today.
Jim

I was not aware of this test. I would like to read more. Do you have a link or a book reference. Thanks for posting

[onelight]

That’s a big difference at 20 yards, I am surprised.
I’m gonna put my heavy springs back in so my 20 yard targets will look like his. That’s gotta be my problem.:bigsmyl2:

[6string]

Hey Guys,
The book this is from is Burning Powder by Doug Wesson.
There's quite a bit about the pre-war 357, and the K-22. While it is intended to promote S&W products, Doug Wesson actually "put his money where his mouth is" through real world experience.
It's available through several sources, including:
http://sportsmansvintagepress.com/product/burning-powder-douglas-wesson/

[rintinglen]

Absolutely, lighter springs can affect accuracy. Back in my PPC days most everybody shot Remington HBWC, either factory or reloads with Federal Match Primers, because those would work in our modified 6 shooters. As an article of faith, it was asserted that such combinations allowed for a trigger pull about a pound lighter than otherwise workable with primers more sturdily constructed. Vertically elongated groups could often be tightened up by raising the poundage on the trigger pull by a pound or so. A useful trick if you want to keep the lighter pull on a S&W, rather than go back to the stock 10-14 pound weight, is to remove the anvil from a spent primer and place it over the end of the strain screw. When you fully tighten the strain screw the added length will usually be enough to strengthen the spring tension enough to allow for consistent ignition.

[Petrol & Powder]

Doug Wesson tested exactly this using the "new" 357 magnum 245983
Using the machine rest at the S&W factory, he showed the effect of reducing mainspring tension on accuracy. The results were remarkable! At 20 yds, six shots clover leafed into one tidy hole when the spring was at full tension. When reduced, the group opened up to greater than twice the size.
This was in the 1930s. Not sure how much changes in primer formulation would affect results today.
Jim

This demonstrates what the GUN is capable of. Notice the test is from a machine rest. We don't shoot guns from machine rests, we shoot guns from our hands. This brings us back to the optimum combination which is, "we want the fastest possible lock time while maintaining a manageable pull weight".
Well trained shooters with good hand strength can take advantage of the faster lock time. This is one of the reasons that practice yields more improvement in scores than tweaking guns. There's no magic mainspring (heavier or lighter) that will make you a better shooter.

When released at full travel the hammer is accelerated by the mainspring. The mass of the hammer resists that acceleration and the spring overcomes that inertia. However, as spring weights are increased, there are diminishing returns in terms of hammer speed. You can't just keep making the spring stronger, you'll reach a point where the hammer just will not accelerate significantly faster. At that point increasing spring weight will only serve to make the DA pull heavier and the shooter will struggle to maintain sight alignment.
SO.......you want the fastest possible lock time (strongest mainspring) that yields a manageable DA pull weight. Turns out, that work has been done for you and that combination is often obtained with the factory mainspring.

And the trick of placing a spent primer cup over the strain screw is generally applied because:
A. someone had previously shortened the strain screw (a bad practice) OR
B. The mainspring had become weaker over time.

[onelight]

I need to do some more testing on some of my guns . If I was not getting any light strikes I was calling them good. That’s not necessarily true.

[6string]

The original post asked Can Springs Affect Accuracy?
The answer is "Yes".
But, perhaps not as badly as I seem to have implied (see below).:?

Doug Wesson's just wanted to emphasize the importance of uniform ignition, and probably discourage folks from getting carried away with messing around with the factory adjustments.

For those of you interested in Mr. Wesson's results, please read his chapter on revolver accuracy. (Like I should have re-read!) He puts the test in context of overall design and workmanship, with respect to Smith and Wesson products. He states, also, that their service grade revolvers have the same accuracy potential as the target arms, the difference being sights, trigger type, and action fitting.

I made a big mistake in my original reply. The image I should have posted is this one: (sorry!)

246014

Here's a link to an excerpt:
http://sportsmansvintagepress.com/read-free/burning-powder-table-contents/smith-wesson-revolver-accuracy/

[onelight]

Thanks for posting that correction , quite different .
My bench testing is hand held with max range of 25 yards where I shoot the most with my skill level I might have a hard time seeing much difference but might be fun to experiment .

[tazman]

Interesting article. Thanks for posting.

[6string]

Interesting article. Thanks for posting.

Glad to be able to offer it.
Again, sorry for my earlier mistake.
But, even with the smaller difference, I'd personally go for every accuracy edge I can get. That test was at 20 yds. At 50 yds, my usual pistol shooting distance, the issue becomes more of a problem.
Jim

[Drm50]

I have a good bit of experience with S&W revolvers. I have seen guns with aftermarket mains than had silk smooth SA pull and shot all over because of UN uniform ignition. Some use strain screw for trigger pull adjustment. Does the same thing. Also the spring is designed to take the load screwed down tight. The backing of of strain screw changes the nature of the load and can cause the spring to snap. Likewise I have seen guys thin the main spring to lighten pull. This usually ends up with broken main too.