Originally Posted by TN.Frank
If anyone wonders why I went with the 13# trigger spring it's because the factory spring(blue color) was the same length as the Wolff 13# so it looks like the factory had a light spring in this gun from the get go so that's why.
Don't make the mistake of thinking a factory spring may be similar to some other aftermarket spring just based on overall length. The number of coils, outer diameter, wire gauge and hardening can make for differences.
The factory rebound slide spring for the J-frame is painted light blue, has 15 coils and is a flattened closed-end design spring. (K/L springs are unpainted and have 17 coils, but also have the same outer diameter as the 15 coil spring.)
The rebound slide spring is the number one "safety" in S&W revolvers. (In external hammer S&W revolvers the hammer block and minimum single action trigger pull weight are additional safeties.) Cutting spring coils off the factory spring, or using a lighter rated aftermarket spring, can impede the speed of the rebound slide.
Also, and perhaps more noticeably for owner/shooters, lightening the rebound slide spring can result in a slower, and perhaps less brisk trigger recovery.
How fast trigger recovery occurs affects how fast you can fire the revolver (without short-stroking it).
I remember when the former revolver armorer installed one of the reduced power rebound slide springs in my first 642-1. The first (lightest) spring he tried wouldn't reliably let the trigger recover in dry-fire bench checks. The next heaviest reduced power spring let the trigger recover almost
all the time during dry-fire checks. The heaviest of the reduced power springs that came in that pack let the trigger recovery all the time during dry-fire. It stayed in the 642.
However, after a few months of a lot
of shooting in various drills, especially those involving fast-paced shot strings, the faster my revolver skills returned, the more often I noticed that sometimes my trigger finger was having to "wait" for the trigger to recover before I could fire the next shot in the more demanding rapid-fire drills. Hmmm.
I removed the reduced power rebound spring and replaced it with the factory spring. Suddenly (surprise, surprise), my trigger recovery was faster and seemingly more brisk. It easily kept up with my trigger finger.
Now, if trigger recovery speed isn't a concern, think about something else ...
Sometimes a particular DAO snub might find itself having to be fired under less-than-ideal conditions, meaning abuse environmental conditions, owner neglect (poor maintenance practices), etc. Thins which may have an adverse influence of the rebound slide moving, meaning things which might adversely affect trigger recovery.
In such an imagined set of conditions, which spring do you want in your 642? The strong factory spring? Or the lighter aftermarket spring?
Having experienced having my 642's trigger not recovering fast enough for me to fire subsequent shots as fast I I wanted to fire them during some fast-paced drills, I never want to feel that again, myself.
A lighter hammer spring may create the potential for light-strikes which may not ignite a primer. Add in the same less-than-ideal influences and conditions that may occur for any particular shooter/gun, and a lighter hammer spring's lacking the force of the factory coil spring might become a potential issue at some time or another.
Now, if it's just a leisure range gun, used for target shooting or sport, then it might not be an issue that would concern some owners, as all they risk is not punching a hole in some paper target, plinking target, etc.
All of my
half dozen J's use the factory mainsprings and rebound slide springs, but then I only have them for use as dedicated defensive carry weapons.
Just my thoughts.
Congrats on the new 642.