Lightening the trigger pull of a S&W

[Blondie.357]

I have seen the method where one takes out a spring inside the gun and puts another one in but why do that instead of just loosening up the screw at the bottom of the pistol grip?

I always thought my 686's double action pull was a tad bit on the heavy side, so with a couple turns I made it much smoother.

Am I missing something here or is really just that simple?

 

[drail]

No it's not quite that simple. Loosening the tension screw for the mainspring will reduce the pull but it will also lessen the amount of energy delivered to ignite the primer. Some brands of primers require a fairly good hit to set them off reliably. Reducing mainspring tension will cause misfires at some point. Reducing it past a certain point will cause the mechanism to bind (called "knuckling" by smiths.) To reduce the trigger pull correctly you must reduce the friction in all of the moving parts while attempting to maintain enough spring tension on the hammer and trigger return to ensure 100% function. It's a careful balancing act.

 

[ClayInTx]

I think you have a screw loose.
Sorry, couldn't resist.

I don't believe I would loosen a screw on anything unless it was an adjustment screw with a lock-nut to maintain the adjustment.

 

[drail]

Correct. The tension screw needs to be tightened enough that it cannot back out. (Loc tite is not a bad idea either) If you have ever seen Jerry Miculek shoot a revolver one of his most amazing feats is doing what he does with a revolver with stock or even heavier springs. He cycles the action so fast that with a stock trigger return spring he would have to wait for the trigger to return forward. He needs it to reset very fast. His guns are smooth but not lightly sprung. His hands are incredibly strong but precise.

 

[Japle]

Loosening the mainspring tension screw reduces the trigger pull, but it also changes the angle of the spring. Not much, but it makes the initial movement harder and can lead to spring breakage.

There's a spring set that you can get from Brownells - http://www.brownells.com/.aspx/pid=1474/Product/MICULEK_REVOLVER_SPRING_KIT - that does the job very well. Jerry Miculek's DVD on S&W trigger jobs is also a real good investment IF you're good with tools.

 

[Blondie.357]

Ahh, ok. I'm going to tighten it up to the max then. I don't want a weak firing pin.

Thanks for the spring link.

 

[drail]

In time your hand strength will increase and you won't even notice the pull weight. You can run pretty light spring weights if you stick to using only Federal primers. But a gun that will pop a Federal primer every time will usually start misfiring with CCI primers. The thing you must learn with a DA revolver is to pull the trigger and then allow it to reset fully.

 

[Casimer]

Blondie it is possible to reduce your mainspring weight a bit without encountering ignition problems. But the range of adjustment is limited, and requires some testing to confirm reliability.

I'd read your other post, where you'd described trying to find a gunsmith to perform a trigger job on your 686. Hopefully you can find someone who's competent. Because you can set-up a very nice DA pull, that's still reliable, on your revolver, but it will involve much more than changing the mainspring weight.

If you're willing to post your location here, or in the smithing forum, someone may be able to recommend a gunsmith who can help you out.

 

[Elvishead]

I know 12 gunsmith's that can help you.

 

[PAdutchman]

I just installed a Wolf reduced power mainspring & a 14# rebound spring in my S&W 67 two days ago. I had never changed springs in a revolver before. It took me about a half an hour, and 15 minutes of that time was making a tool to remove the rebound spring. It made a fantastic improvement in my trigger pull. I used a digital trigger pull guage to get an average over 5 tests before and after. The results were:

Before the change: Single action pull was 4lb-11oz & Double action was 11lb-7oz

After the change: Single action pull was 3lb-6oz & Double action was 8lb-1oz

It was worth the $10 cost as far as I'm concerned.

 

[SaberOne]

Perhaps you may find these two articles interesting, as they are quite descriptive to the subject. Mr. Cunningham explains the positive and negative aspects to certain trigger adjustments.

http://www.grantcunningham.com/good_trigger.html

http://www.grantcunningham.com/blog_files/action_performance.html

 

[salvadore]

Prior to wollf, people would lighten their own springs by removing metal from the mainspring and removing coils from the trigger rebound spring. I do this on all of my K, N and L framed Smiths

 

[Blondie.357]

Perhaps you may find these two articles interesting, as they are quite descriptive to the subject. Mr. Cunningham explains the positive and negative aspects to certain trigger adjustments.

http://www.grantcunningham.com/good_trigger.html

http://www.grantcunningham.com/blog_...rformance.html

Interesting read. Thanks.

 

[jad0110]

To reduce the trigger pull correctly you must reduce the friction in all of the moving parts while attempting to maintain enough spring tension on the hammer and trigger return to ensure 100% function.

This.

Crappy trigger pulls in handguns are usually caused by the following two broad categories: (1) tool marks and/or rough spots on the engagement surfaces and (2) ill-fitting components. Either problem can increase friction or the amount of leverage required to cycle the action. This not only results in a heavier than normal pull, it can also cause a trigger to feel “gritty”, “rough”, “scritcy”, “junky” … whatever.

With most S&W revolvers, the problem is usually #1, particular when the gun is NIB. If this is a new gun, give it time to break in. Most NIB S&Ws have rather stiff/gritty pulls from the factory, even Performance Center guns, but dry fire it a couple thousand times and it should smooth up nicely. Most of the time, this is all that his needed to slicken up the trigger on a S&W. I bought a new in the box 642, that while stiff and gritty at first, now has a very smooth trigger.

There are exceptions. If the tool marks and/or rough spots are too extreme, it may take a qualified gunsmith to polish away the friction in the appropriate areas. And improperly fitted/sized parts, well, only a gunsmith can cure that problem.

From what I understand, the more severe tool marks and rough spots are usually found on the frame and sideplate where the rebound slide travels. This is often the source of the S&W “scritchy” feeling DA trigger, where there is a grinding sensation in the DA trigger in the last 1/8” of the pull (feels like sliding two dirty pieces of glass against each other); my 686 has this problem even after thousands of live and dry fire exercises. It needs the help of a gunsmith, I just haven’t gotten around to it.

The problem with loosening the strain screw and swapping or chopping springs is that you are likely treating the symptom only. Sure, the pull will feel lighter, but the friction that caused it to feel heavy in the first place will remain, whether it is caused by rough spots or ill fitted parts. What you will have is a light, rough trigger. Kinda like that found on many NIB, lower end 1911s. Light triggers are very often mistaken for good triggers, but this is not always the case.

 

[drail]

One other disadvantage of lightening a trigger by only reducing spring weights is this will make the lock time longer. If the hammer is falling slower it is easier for the shooter to throw the shot off because the gun now has more time to move off target. The less time between sear release and primer hit the better your chances are of not moving the gun off target. Most really good target shooters will actually install higher weight springs under the hammer for a faster lock time. If the friction factor is taken out of the mechanism you can still obtain a good crisp trigger. I didn't want to believe this at first but have found it to be very true.

 

[salvadore]

I agree about lock time, and if I only shot single action there are better ways to improve trigger pull if needed. One of the reasons I shoot my double action guns double action 99% of the time is lock time and this is just anecdotal personal experience, I do much better with my Smiths and Colts after grinding snipping and bending than before.