Strain Screw

[Blued Steel]

I have a 586 no dash. Trigger has been worked over by a s&w master. Trigger is phenomenally smooth in DA and super light in SA. Cocking the hammer is super smooth and trigger reset is butter smooth also.

I bought the gun second hand but the credentials for the trigger work came with the pistol as if it was a declaration of independence.

It says that if I experience light primer strikes I should turn the strain relief screw in 1/4 turn, however.I should use federal primers and ensure I am seating them correctly as that is likely the cause for light primer strikes. It also says I should send the pistol back to the guy once a year for servicing. The guy has since retired.

Being this was my first pistol and first time reloading, when I got light primer strikes(like...1 out of 50) I didnt immediately touch the screw. I started seating ALL of my CCI primers with more force on my lee tool. I've also started using win primers as well as cci. Since I started cranking the primers home more, I've never had an issue

But... reason for this thread... is I havent ever come across a trigger job info peice where it ever reccomends touching the strain screw...and I've come across a lot of info mentioning the screw should ALWAYS be bottomed out.

Is it acceptable practice to do a professional trigger job and send the pistol out the door with a backed off strain relief screw?
Is a large part of my super special trigger job the fact that my strain screw is backed off? Now that the guys retired, should I take note of where it is currently so I can keep it exactly there? If not tight, will it move on its own?

 

[HorizontalMike]

I had a LGS trigger job on my first 686ND REVOLVER back in Jan 1987. Several years later I decided to redo/check the trigger pull. While cleaning/stoning/measuring, I discovered that my 33yr old "LGS trigger job" included filing the strain screw in order to fine tune the trigger. The easy fix is... order a couple of extra strain screws and redo the pull to you own ideal pull. FYI, buy extras...


Numrich
Strain Screw, Blued (Square Butt) | Gun Parts Corp.

Strain Screw, Blued, New Factory Original (Square Butt)
$3.60
Manufacturer: SMITH & WESSON
Model: K, L, N FRAMES
Product #: 323520


Also, check out this thread:
S&W 686 strain screw replacement

 

[brucev]

First of all, you could not have found a better revolver for your first pistol. The 586, especially a no dash, is outstanding. The action job sounds fine.

Reloading your own ammunition will give you great pleasure as well as allow you to develop your shooting skills. Primers vary in sensitivity. For better or worse, CCI have a reputation for being a bit "hard." Many folks use Federal primers b/c of a reputation for being easier to ignite when using a lighter action.

Opinions are like noses. When it comes to strain screws, this opinion/nose thing is worth remembering. For a revolver that will be used for unpleasant social interactions ... reliability in firing regardless of the circumstances is paramount. Do everything possible to make sure the revolver will fire 100 % of the time. This means of course to tighten the strain screw down hard. This will guarantee the hammer has sufficient power to ignite even a hard, stubborn primer.

For a revolver set up for and used for range or roaming the woods and fields, a light action with a finely adjusted SA and DA is helpful to good marksmanship. It is just a delight to use. Set the strain screw to work positively with your selected primers. If the strain screw should show signs of moving, use a little bit of Loctite. It comes in a number of types. Use the type that merely keeps a screw from accidental movement. HTH. Sincerely. bruce.

 

[NYlakesider]

I have a 586 no dash. Trigger has been worked over by a s&w master. Trigger is phenomenally smooth in DA and super light in SA. Cocking the hammer is super smooth and trigger reset is butter smooth also.

I bought the gun second hand but the credentials for the trigger work came with the pistol as if it was a declaration of independence.

It says that if I experience light primer strikes I should turn the strain relief screw in 1/4 turn, however.I should use federal primers and ensure I am seating them correctly as that is likely the cause for light primer strikes. It also says I should send the pistol back to the guy once a year for servicing. The guy has since retired.

Being this was my first pistol and first time reloading, when I got light primer strikes(like...1 out of 50) I didnt immediately touch the screw. I started seating ALL of my CCI primers with more force on my lee tool. I've also started using win primers as well as cci. Since I started cranking the primers home more, I've never had an issue

But... reason for this thread... is I havent ever come across a trigger job info peice where it ever reccomends touching the strain screw...and I've come across a lot of info mentioning the screw should ALWAYS be bottomed out.

Is it acceptable practice to do a professional trigger job and send the pistol out the door with a backed off strain relief screw?
Is a large part of my super special trigger job the fact that my strain screw is backed off? Now that the guys retired, should I take note of where it is currently so I can keep it exactly there? If not tight, will it move on its own?

I have never heard of a GOOD gun smith that will not tighten up the strain screw all the way.

Heck I do most of my own revolver work, im far from a "gunsmith" and I know that.

I bought a gun that was supposed to be done by a very well know Smith. Had the lightens best trigger pull on a DA revolver I ever shot. Got every 3 round as a miss fire. I decided to check things out and perhaps replace a spring or two to get the gun right.

Pulled the grips and found the strain screw had about 1/2 a turn to be tight. OBTW that fixed the gun and it still has a outstanding trigger pull.

I will never mention the name of the Smith as I doubt he let the gun go out of his shop that way.
I have shot the gun a bit and the screw has not loosened a iota so I guess the previous owner tried to make the great trigger pull even better!

 

[hogblue]

Make sure the strain screw is screwed in until it bottoms out. The two things that cause light primer strikes are the strain screw not seated all the way in or too much end shake.

Also check to see if he ground off some of the tip of the strain screw or ground off some of the sides of the main spring. Those are two other tricks used by older non gunsmiths to lighten double action trigger pull and makes for light primer strikes and unsafe unreliable weapon.

If that revolver came with instructions from the so called gunsmith to turn the strain screw in and you’re having light primer strikes, he is not a smith and wesson revolver gunsmith.

 

[gwpercle]

If it isn't broke ... I wouldn't fix it myself .
If I started experiencing "light strikes" I would tighten the strain screw 1/4 turn , start using Federal primers and if none of that worked I would get it too a good shop ( In La. Clark Custom Guns) for repairs .
I would not send it back to S&W .
Gary

 

[scattershot]

If you are experiencing light strikes with the strain screw all the way in, a thin pad of leather between the screw and the spring should fix it. F it were mine, I’d go ahead and tighten the screw all the way down and see what happens. That way, you know it won’t change, and it will fix the light strike problem.

 

[stu1ritter]

If you follow the advice found in the S&W armorer's manual you can adjust the length of the strain screw to the minimum hammer weight and it will fire all primers made. For 357 that is 3.5 pounds. Copies of the two pages from the armorers manual are shown below. Personally, I've done perhaps 70 revolvers this way and it always works. Set properly you will probably have a stupendous trigger with a strain screw that is nice and tight and not adjustable.
I use a small pail with a mix of lead ingots and lead bullets and a scale to equal the hanging weight set.

Stu

 

[minconrevo]

I won't leave a strain screw in other than a fully tight against the frame state. That's for either a carry/duty or a game revolver. They walk loose. Don't go filing material from the end of a strain screw until you have at least a couple exact match full length ones in hand. To reduce a little screw length without filing, I have used a small split lock washer just under the screw head. Takes a fine touch to carefully spread open the washer then close it mostly up again, so that it will fit in the screw head recess in the frame.

That hammer blow must be true and straight, with no rubbing on either the frame on one side or the screwed down sideplate on the other. SS hammer shims carefully applied can accomplish this.

 

[ken158]

If you follow the advice found in the S&W armorer's manual you can adjust the length of the strain screw to the minimum hammer weight and it will fire all primers made. For 357 that is 3.5 pounds. Copies of the two pages from the armorers manual are shown below. Personally, I've done perhaps 70 revolvers this way and it always works. Set properly you will probably have a stupendous trigger with a strain screw that is nice and tight and not adjustable.
I use a small pail with a mix of lead ingots and lead bullets and a scale to equal the hanging weight set.

Stu

That is an updated page from my armorers manual but continues to stress keeping the main screw tight. I was taught the main screw filing method by the course instructor before printed instructions were included. Good to know the manual was updated on that topic and likely other topics. A good gunsmith would never use the main spring tightness as an adjustment that was not screwed in tight.

 

[oysterer]

Try federal primers first and I doubt you will have a light strike.

I do believe backing the crew out a 1/4 turn is NOT the end of the world. It is a tight fitted screw with a large head. To make extra sure put a small dab of blue locktite on it and set it where you want it, it won't go any where and that is better than stoning around on it I find.

 

[WR Moore]

OP, your instructions suggest the gun was reworked by someone familiar-but not expert- with formal competition. Most likely, PPC, but that usually resulted in the firearm being changed to DAO so it wouldn't have to pass single action pull tests. Work by renowned master PPC smiths often included the adjustable strain screw feature, but those guys generally also included a separate locking screw (up through the butt) to keep the adjustment from changing mid-match.

The idea was to provide the ability to adjust for the available primers/ammunition while still maintaining the lightest possible (under rules) trigger weight.

As noted above, if the firearm is a piece of sporting equipment, the current situation isn't the end of the world. It'd be good idea to run the screw in full depth while counting turns to figure out what the current setting is supposed to be. Write that down somewhere for possible future reference. Loc-Tite (blue) is always an option if used cautiously.

Now about strain screws. A couple years ago I did the adjustments mentioned in post #8 (strain screw seated fully) and discovered that there can be a considerable variation in length in lots of strain screws. I got a new one that was shorter than the screw I'd already ruined by cutting it too short. I did eventually get the deed done correctly. BUT, while doing so discovered that part of my problem was not bottoming primers out in the primer pocket (seat by feel my donkey), part was my manipulation of the trigger and the final part of the problem was the after market hammer spring. The last got replaced with a factory spring.

If the firearm might become more than a piece of sporting equipment, the advice by Stu is the gold standard. Loc-Tite works. Yes, a backed off strain screw can back out. My limited experience is that just how far it's backed off (load on the screw to keep it from moving) does make a difference. Best to be safe if you might be using it for other than paper punching or like to have everything exactly "right".

 

[Protocall_Design]

Everyone has their own opinions on this subject. They are each adamant that their way is the ONLY way. All are entitled to do as they see fit. This is my opinion after 40+ years of building and tuning custom S&W and other brands of revolvers for competition.

If you are using a particular gun ONLY for target or competition use, you can afford to back off the tension on the strain screw to get a lighter trigger pull. If you back off the strain screw without thread locker, it will gradually continue to back out as you're shooting, till it gets too light to fire.

DO NOT lighten the springs on a carry or duty gun.

Every gun is an individual entity, so blanket statements will get you a gun that works, but not one that has the best action it can have. There are many variables in play, including the gun with all it's numerous parts, variations in headspace, firing pin length, endshake, length of strain screw, thickness of mainspring, etc. and the ammo, with many different kinds of primers, seating depth, rim thickness, etc. All these variations (and more), and different combinations of them, means that it will take a different hammer strike to reliably set off the primers in a particular gun with a particular kind of ammo.

The best EASY way I've found to get a good action is to clean the strain screw and hole with solvent, put blue 242 Loctite on the screw and lightly tighten the strain screw. You can make an access hole in the grip if you like, to adjust the screw without removing the grip. I prefer a #8-32 x 3/8" or 1/2" setscrew. The 3/8" length is for round butt frames.

Go to the range and keep turning up the tension on the strain screw in 1/8 turn increments until you are not getting any more misfires in D/A. Then give it another 1/8 turn to catch the 1 in 100 misfire. Using a trigger pull gage, record the weight it takes to start the hammer moving when pulling on just the hammer. If you need to undo the mainspring, you can easily reset it to that number on the pull gage.

Then find the lightest rebound spring that gives you the rebound feel you want and you will have a pretty decent action.

 

[HorizontalMike]

Oops, an added explanation.

• While doing slow DA firing, I never had an issue.
• When conducting rapid DA firing, I would get light strikes. This led me to look into this deeper.
• For many, many years, I would only practice with SA and never had a FTF. So my FTF/light strikes were never noticed.

So, I would suggest always practicing all methods of firing just to be safe and sure that you don't have any FTF/light-strikes.

I had a LGS trigger job on my first 686ND REVOLVER back in Jan 1987. Several years later I decided to redo/check the trigger pull. While cleaning/stoning/measuring, I discovered that my 33yr old "LGS trigger job" included filing the strain screw in order to fine tune the trigger. The easy fix is... order a couple of extra strain screws and redo the pull to you own ideal pull. FYI, buy extras...


Numrich
Strain Screw, Blued (Square Butt) | Gun Parts Corp.

Strain Screw, Blued, New Factory Original (Square Butt)
$3.60
Manufacturer: SMITH & WESSON
Model: K, L, N FRAMES
Product #: 323520


Also, check out this thread:
S&W 686 strain screw replacement

 

[WR Moore]

Oops, an added explanation.

• While doing slow DA firing, I never had an issue.
• When conducting rapid DA firing, I would get light strikes. This led me to look into this deeper.
• For many, many years, I would only practice with SA and never had a FTF. So my FTF/light strikes were never noticed.

So, I would suggest always practicing all methods of firing just to be safe and sure that you don't have any FTF/light-strikes.

1. Hammer travel in DA is shorter than in SA. This can make a difference.

2. If the trigger isn't held all the way back in DA while the hammer is falling, the secondary double action surface on the trigger can brush the hammer foot and slow the hammer fall. If you're in a "real hurry" you might fail to do this.

 

[Sevens]

Lots of good info in here but there is some ridiculous fluff also.

There are world renowned pistolsmiths that made incredible competition revolvers out of S&W K&L frames (and a few N-frames) and altering the length and depth of the strain screw is absolutely a part of a large package of work. It isn’t even difficult to find Youtube videos of Jerry Miculek discussing exactly how he alters a strain screw for his uses (and Jerry doesn’t use the lightest trigger, that’s for darn sure)

The folks who vehemently argue that “no good gunsmith would lessen, shorten or screw out a strain screw” are outta their minds and have never had a Power Custom, Strahan, Behlert or Bill Davis revolver in their hands.

These revolvers were designed to run Federal 100 primers. Mine are phenomenal.

 

[garbler]

Lots of good info in here but there is some ridiculous fluff also.

There are world renowned pistolsmiths that made incredible competition revolvers out of S&W K&L frames (and a few N-frames) and altering the length and depth of the strain screw is absolutely a part of a large package of work. It isn’t even difficult to find Youtube videos of Jerry Miculek discussing exactly how he alters a strain screw for his uses (and Jerry doesn’t use the lightest trigger, that’s for darn sure)

The folks who vehemently argue that “no good gunsmith would lessen, shorten or screw out a strain screw” are outta their minds and have never had a Power Custom, Strahan, Behlert or Bill Davis revolver in their hands.

These revolvers were designed to run Federal 100 primers. Mine are phenomenal.

Couldn’t agree more. I trained with Ron Power and built plate and pin guns for years. At the time all action jobs were set up on Fed primers unless the owner specified different. Hard core competitors often had to manage the mainspring for ammo and match conditions but most good smiths gave the owner a base line to work from. For those who those who don’t drive race cars it’s often hard to understand why the interior is so ratty.

Rick

 

[stu1ritter]

Finally dug up some additional Hammer Weight info from a gent who used to build competition guns and had posted here but I haven't seen him in awhile.
This information is from his fingers........I have found it quite accurate and useful. The custom shop settings apply to well polished lock works.

And for those of you buying strain screws from Numrich for $3.60, they are only $1.58 from the factory.

Stu

Factory:
357 mag: 56 oz
38 sp : 52 oz

Custom Shop:
357mag: 42 oz
38 sp: 38-40 oz
Target hammer: 44 oz with stainless spring
Old style target hammer w/ blue spring 52-54 oz
K frame rimfire: 40-42 oz.

Older hammer noses must have good springs
Moon clips too much variables fire testing required
Stainless springs are a bit stiffer
These settings are never full proof but close.
On competition guns, blue loctite on the strain screw screwed down tight!

 

[series guy]

Instead of ruining the original strain screw I put it in a ziplock bag along with the stock mainspring and rebound spring. I use a McMaster set screw # 95235A507 with built in nylock for an infinitely adjustable screw that won't loosen.

 

[Blued Steel]

Holy lots of info. Thanks for all the replys and info. Guess its 6 of 1 half dozen of the other. Sounding like it is acceptable practice to back off the screw depending on the use of the gun.

The action work was performed by Murray Charlton...reputable guy as far as I know. I went and dug up the sheet of paper the pistol came with and he calls it the "distinguish tune, ready for the distinguish match". Recommends using federal primers, and says if experiencing light strikes check/make sure primers are being seated properly. If still experiencing light strikes, turn screw 1/4 turn initially and shouldnt need more than 1/2 turn total.

Since I started seating CCI primers with more pressure I havent had light strikes... but I also started shooting pretty much exclusively SA around that time as well.

I'll try DA and see how it is. May switch out to federals next primer purchase if its an issue. And go from there.

I quite like the trigger the way it is now... I think I'll use a paint pen and mark the screw where its set now and keep an eye on it to make sure it stays put.

In any event, sounds like the screw being backed out is part of the package and is of sound practice for a target pistol. Thats mostly what I wanted to confirm.