Adjusting trigger on 625-8

[Husker95]

Hey guys, need some advice on my 625-8. I got a trigger job done about a year ago and it ran great – I really liked the work and thought it improved my overall performance a bit. About 3 months ago, I took it to a small, local match and it malfunctioned big time. I couldn’t fire any of my standard ICORE rounds. Turns out the strain screw had backed out and my trigger drop (?) was way too light. One of the guys at the club took it and screwed the strain screw all the way in so I could finish the match. Now it will break every primer I have but the trigger pull is factory heavy again. Its still smoother than it was out of the factory, but id like to get back to the lighter/smoother – but reliable – place that it was right after the action job. What is a “best practice” method to do this? Thanks for putting up with this basic question.

[Bubber]

Husker95, In a perfect world the strain screw will not lossen up...But.. The main contention is that the strain screw should be bottomed out and locktited. Which means you would do some trial and error to get the right length of the strain screw, bend the mainspring to get reliable ignition. I don't know what you mean on trigger drop. The process has been discussed in the revo section and you may be able to find it doing a search on "trigger pull" "lightening the trigger" later rdd

Edited to add link an fix ma spellin STRAIN SCREWS!!

Edited May 18, 2009 by Bubber

[Husker95]

I knew i had misphrased that. I should have said "hammer drop", - the weight/force the hammer had as it went forward. When he measured it before tightening the strain screw back up, the guy at the club said it was way to light for anything but a bobbed, spurless hammer. I think it was less than 3 pounds.

My initial thought was that i should start backing the strain screw out by whole or half turns until it breaks all my Fed primers consistently but still feels smooth and lighter. And then loctite it with the less-than-permanent loc-tite. Is that the standard procedure?

I have a standard hammer (non-bobbed) - what is a typical trigger pull/hammer drop in poundage after an action job that is still reliable for fed primers?

I will check the archives for info as well. thanks for the advice - as you can tell i am new to the insides of a S&W.

Husker

[Matt Griffin]

I knew i had misphrased that. I should have said "hammer drop", - the weight/force the hammer had as it went forward. When he measured it before tightening the strain screw back up, the guy at the club said it was way to light for anything but a bobbed, spurless hammer. I think it was less than 3 pounds.

My initial thought was that i should start backing the strain screw out by whole or half turns until it breaks all my Fed primers consistently but still feels smooth and lighter. And then loctite it with the less-than-permanent loc-tite. Is that the standard procedure?

I have a standard hammer (non-bobbed) - what is a typical trigger pull/hammer drop in poundage after an action job that is still reliable for fed primers?

I will check the archives for info as well. thanks for the advice - as you can tell i am new to the insides of a S&W.

Husker

There are several schools of thought, including your method, grinding down the screw, and bending the mainspring. I like having the screw bottomed out, so I went with spring bending. I backed the strain screw out 1/2 turn, then bent the spring until I had a failure. I then locked down the screw and it seems to run well.

H.

[Husker95]

thanks Houngan. Since i made my last post i read some of the posts in the thread that Bubber posted. I like the idea of a shortened strain screw scrwed all the way in. Its simple with limited chance of failure. I am not comfortable with bending the mainspring yet - just dont feel like i have the expertise. Right now i am thinking i will back it out until i have a failure, go back in, measure the screw and then grind it down to length and screw it down tight. Does that make sense? thanks.

Husker

[Matt Griffin]

It does, but don't take my word for it; spring and screw interact in some magical ways, and I'm a novice. Pinshooter can produce a fantastic trigger, as can Carmoney, I've tried both. Others will know more as well, but there are a lot of factors. Do you still have a full hammer? That's one of the easiest things to change, chopping off the back and lightening it.

H.

[ihatepickles]

If you'd like to experiment with some revolver work, order a new strain screw or two and a Miculek Spring Kit. You won't be out much cash, and you'll have the original unmodified parts to put back in if you don't like the results. I would order a couple of strain screws though, they're handy to have around.

Edited May 18, 2009 by ihatepickles

[Carmoney]

Adjusting the mainspring tension by simply shortening (or backing out) the strain screw, without adding additional arch to the mainspring, can create a condition known as "knuckling" if you go too far. In my action jobs, I generally shorten the strain screw somewhat, and combine that shortened screw with a mainspring that has been properly re-arched. Then you have to balance the rebound slide spring to the newly-adjusted mainspring, and lock the strain screw down with blue loctite. This method will prevent misfires indefinitely (assuming only properly prepared ammunition is used in the gun), and maximize the potential of the S&W double-action pull without running into that knuckling problem.

[pskys2]

Mike's solution is perfect. By using a slightly shortened strain screw (with a properly adjusted Main Spring) you can have a spare full length screw in your bag, just in case you end up somewhere you HAVE to use Factory Ammo, or non-Federal Primers.

[Husker95]

Thanks for all the input guys; i really appreciate it. I think my mainspring might have already been arched, or bent. I had an action job done by a local guy and like i said it ran great for a long time. Then the strain screw backed out to far and started to malfuction. So, if i find our where the strain screw tension needs to be, cut the screw and then screw it in all the way - i should have my action job back. True?

I am also going to get a trigger-pull guage. That seems like an essential piece of equipment if your going to own a revo.

Husker

[Gregg K]

Once you find out where your strain screw should be, it's easy to figure out how much to shorten it. The screw has 32 threads to the inch so if you find that the screw is perfect when it's backed off say 1 full turn then just shorten the screw by that much. Divide 1000 by the threads per inch and you find that 1 turn is equal to .03125 so measure the length of your screw and then shorten it the right amount, take off .031 for 1 turn, about .010 for 1/3 turn and so on.

Once you have the length right just bottom it out HARD and never have to worry with it. If you have the right screw drivers to really crank down on it hard it will stay put or just add some loctite as others have mentioned. I keep a spare strain screw with me to keep Murphy away but have never needed it.