S&W 625JM trigger job woes

[DLS]

@Lesliet

This is a continuation of a the trigger job postings that started in the What Did You Load Today thread. I thought it would be better to continue it in its own thread.

What did you reload today? | Northwest Firearms - Oregon, Washington, Idaho, Montana, and Wyoming Gun Owners Posts 1686-88, 1691

So, hmmmmm ....

It didn't work out like I thought it would. As stated in the other posts, I installed the Brownells / Wolff spring kit consisting of their reduced power mainspring and a 13# trigger rebound spring. This created a DA pull weight of 6 pounds, which as I expected, barely dented the CCI primers I was using when I tested fired the gun on Monday. They looked like the primers on an AR15 after chambering but not being fired. There was a barely discernable dimple.

So today I reinstalled the factory mainspring and left the lighter rebound spring in place. This brought the DA trigger weight to the 12# range which is 2# lighter than when the innards were unpolished using the stock rebound spring. This was heaver that I wanted so I backed off the strain screw a full turn bringing the DA trigger to the 7.5# range, but I got about 30% misfires at this setting.

Turning the strain screw in a half turn (so it's basically turned out 1/2 turn from full bottom position) gave a just over 10# DA trigger and 100% firing of the last 24 rounds I had available for testing. I'll run some rounds through the gun tomorrow and see if the reliability is still there.

I was hoping for a better DA trigger than this. I've worked on a lot of Ruger DA revolvers and have no problem getting them down in the 8# range with no misfires even with CCI primers. I've helped folks polish out their S&W revolvers in the past since it's easy to do, but never messed with the springs until now. I'm surprised that the Wolff spring kit so drastically lowered the weight to the point of utter unreliability. I wonder if I have a defective main spring, because I really don't think my revolver could be that far out of spec. What do you think?

I'll play with the strain screw a bit more tomorrow as well as I really would like to get this trigger at least in the 9# range. I may need to do some more polishing since there seems to be a bit of roughness as the trigger just starts to move. I can always get a shim set too, that might get rid of the roughness. While the parts are out of the gun I can bevel the corner of the trigger just at the top of the arc shaped portion. This corner digs into my trigger finger when shooting DA. It dug into my son's finger too. I'm surprised S&W would have such a sharp spot on their triggers, I can't be the first person to have this issue. I've never messes with smoothing MIM parts, and this gun has an MIM trigger and hammer. Since I'm just touching the corner with a stone to cut the sharp edge I don't think I'll have any issues, but if you know of something I should look for please let me know!

I've heard some folks get really worked up saying you should never use the strain screw for adjusting the trigger weight and that it needs to be fully seated at all times? Do you know why? Why have the screw in the first place otherwise? With Loctite a drifting screw would not be a problem, and you could always get an overly long screw and grind it to the correct length if you really wanted to bottom it out for some reason. So, If you can enlighten me on this I'm happy to learn!

Another bummer, one of the new Wilson Combat 1911 magazines that came in my recently purchased 3-pack failed on me. The floorplate just slips off with light thumb pressure. I tried increasing the bend in the small tab protruding from the retaining plate, but it still does not secure the base pad properly. So I have to mess with a return, I really don't like having to do that type of thing. First world problem I know, but it bugs me just the same.

So, I'll let you know how it works out after shooting the gun again tomorrow.

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[Unicykle]

Shooter service does a bang up job with revolvers if you want to have it done right.

 

[ron]

I am surprised the Wolf mainspring reduced trigger pull that much. The ones I've installed did not reduce
the pull that much? I have installed reduce power spring kits in over a dozen different wheel guns with no
problems of failure to fire. As for 1911 mags the old Chip McCormick 'Shooting Star' mags I have had for
20 years have never failed. They work better than the few Wilson mags I have which have failed.

 

[DLS]

Hi @ron

Yeah, I was surprised too, the spring is most likely out of spec is what I'm thinking, there is no way it should be that soft. I'll give Brownells tech line a call next week when I have some time. Sometimes you get pretty knowledgeable folks on the line and they will take anything back if you are not satisfied.

I've done a six or seven Ruger wheel guns with a polish, shims and springs always with good results. I always used the Wolff reduced spring sets, so I was expecting the same results with the S&W. I'll take it to the range tomorrow and tweak the strain screw a bit to see what happens hoping to get it done another pound or so.

I've always heard great things about CM mags but the three pack of Wilson's were on a killer sale so I bit. Two of them ran flawlessly today so I'm betting I'll get the bad one swapped out and I'll be fine, at least for a few thousand rounds

 

[Lesliet]

On the strain screw subject... yeah, there are always going to be people with strong opinions about gun stuff. It's pretty common to loctite and adjust, though, so no reason not to, as long as the arc of the mainspring doesn't get set so that it interferes with grip screws or anything like that. Power Custom sells a kit with Allen screws including a strain screw, some folks match mark the head on it to make the settings repeatable. ( or you can measure and get one at a good hardware store, or McMaster-Carr) My 625 is a pre-lock one, so no mim parts. I haven't had to do any polishing at all of the trigger and hammer, all my gains have been from shims and springs.( May have been polished by a previous owner) I noticed early on that there were rub marks where the hammer was rubbing a bit on the frame, and that had to be tuned out with the shims, since that rubbing robs power from the primer strike. Might be worth turning a keen eye to anything that's stealing power, ie looking for rub-marks on hammer and trigger, bolt,hand and cylinder lock, and smoothing any stamped edges that are still rough.
Competitors I've spoken with have gotten their MIM 929's down to 6.5, but they HAVE to run plain Federals to have it reliable, CCI's are simply a no-go at that weight. This setup also includes the bobbed hammer from APEX.

When I eventually get that Ruger Super GP, I'll be bothering you for advice.... 8 lb would be just fine, if it's smooth.

Edit to add a ps- the reasons I've been given why some people don't want the strain screw anywhere but bottomed out are that it needs to be repeatable, and not vibrate loose. Loctite and counting turns cover both those objections. Typical numbers are 1/4 to half a turn back.

 

[oremike]

My wife has a model 60 smith. It's hers and I don't pay much attention to it other than to keep it fed. One day I shot it and thought it had horrible trigger pull. I traced the problem to the cylinder pin being gummed up.

 

[DLS]

@Lesliet ... Thanks for your thoughts on the strain screw and I'd be very happy to help with the GP100, but I suspect it will be pretty sweet right out of the box. They are pretty easy to work on. There is a document floating around the Internet called something like "The GP100 Body of Knowledge" that is the single best "how to" I've seen. Search around and see if you can find a copy. I'm pretty sure I have a copy somewhere on my computer and will look for it over the next few days and forward it to you. I also have some ideas on what to do on Ruger's that are not listed in than writeup.

@oremike ... I had that happen once during an ICORE match. The gun just seemed to almost seize up in the middle of a string. I finished it by manually turning the cylinder for each remaining shot. As you can imagine ... my string was scored at 30 seconds ... which is the maximum. It killed my aggregate but it's still fun shooting even when things don't go exactly right, and I'm not really in the running at these events anyway.

After my "interesting'" stirng, an old revolver shooter walked over to the safety area to look at the gun, saw what was up and went to his car to retrieve a can of brake cleaner ... which ungummed the cylinder enough for me to finish the other stages that day. When I pulled the gun down after the match there was still a lot of residue, far more than should have been there. Later I figured out what had happened.

The gun was a bit dirty from practice when my son asked to take it to the hills with some friends to shoot, which I allowed. Well, unbeknownst to me, they shot about 400 rounds through it. He did a quick wiped down when returning it since I told him not to worry about cleaning is since I was shooting it again at the next days match and I figured I'd skip a cleaning since it really hadn't been shot all that much and I had a lack of time. I never do this ... but did this time.

It looked pretty much like when I let him take it, dirt wise so I figured they only shot a handful of rounds. Well, that was wrong! And the reloads they were shooting were stoked with Unique ... and we all know how dirty that powder is. So long story short ... it was seriously gunked up by the time I hit the second stage of the match.

I won't make that mistake again.

On to the 625 ...

I had time to run about 35 rounds though it and the all went bang with very good primer indentations at the 10# ish weight it's presently set. I didn't have time to mess with it otherwise, but perhaps tomorrow I can get a few minutes to try backing out the screw bit by bit to figure just how low I can get it and still be reliable. I don't see any problem with this, as green or purple Loctite will ensure it stays in place once I figure out what that place will be.

There is still a tiny bit of crunch just as the trigger begins to move. I'm thinking this is coming from the cylinder lock assembly, I didn't pull that from the gun and polish when I was working on the other parts. It was simply a lack of time. So when I next pull the trigger to smooth over that sharp corner I'll pull those pieces out and dress them up a bit and see if that takes care of what I'm feeling.

So, it's looking like I can get a decent trigger at lease, if not a good trigger using the stock mainspring and one of the trigger rebound springs from the kit. We will see what some further tweaking will do.

Thanks again for the insights gentlemen!

 

[Dave Gannon]

@DLS I have a 625- 8 JM. I installed a Miculek Main and return spring kit. The trigger pull is about 2 1/2 pounds single action and a little over 7 pounds double action. Jerry pretty much tells you it'll only shoot with federal primers reliably when set up per his instructions. That's fine with me. If You are curious you can look at his video on the installation on YouTube you'll see what he says to do with the screw to achieve the appropriate trigger pull. I bought some longer screws and didn't bother trimming it because the grips for over it. Dave

 

[osprey]

I guess if the pistols purpose is only sport/competition, purposely setting it up to only be able to reliably ignite federal primers may be acceptable to some. For me I would never want to hamstring any of my firearms like that especially in today's primer scarce environment.

 

[aasbra]

I have limited experience with working on S&W double action revolver triggers, but have done a polish and spring swap on a few of mine including my 625, 929, and a Model 67. For the 625, I think that I ended up using both the kit springs, but IIRC I needed to re-contour (carefully bend) the mainspring a bit to get the desired pull weight. I think it may have been too heavy as delivered. I used something with a contour as a mandrel and carefully slightly bent the spring to adjust the DA pull to about 8#, as lower than this seemed to result in light primer strikes when firing DA occasionally when using a variety of primers. On this revolver, when I disassembled it initially the strain screw was backed way out (it was used when I got it). I was getting some light strikes in DA firing. I ended up swapping the springs to get a DA trigger pull that would reliably ignite primers.

Probably could leave the strain screw backed out a little with threadlock, which would reduce the spring tension slightly. Not sure if bending the mainspring slightly as I did is a better or worse way to accomplish a similar fine tuning adjustment. I felt better knowing the strain screw was secure, but threadlock would also accomplish this.

I agree with Osprey, that in a time where primers are scarce, I may not always have Federal primers available so I want to try and set my guns up to work with a variety of primers. As long as it's smooth the difference between 6.5# and closer to 8# in DA isn't a huge deal to me once you get used to the pull on a particular gun, but I'm not competing in timed competitions with them either.

 

[DLS]

This will be a gaming gun / range toy only, so I'm not worried about having it work for any other purpose, I have any number of more appropriate firearms for hunting and self-defense. Having said that ...

Okay, it official ... I have come to the point of hating S&W DA revolvers!

Long story short. I got the gun down to a nice smooth 8.25 - 8.50 pounds and was very happy with the results. I was sure I could get it down a bit more with some more tweaking but called it good for now, I have other projects calling for my attention. So a little purple Loctite on the strain screw (which was backed out about 2/3 turn) and I was getting 100% with CCI primers.

About 15 moon clips into my shooting session the trigger started to badly catch just at the beginning of the DA press. It requires very heavy pull to get it to snap past the obstruction, which also kept the trigger from moving totally forward after dropping the trigger. SA mode showed no problems whatsoever.

So I pull the gun down to investigate and find nothing other than a faint arc line where the hand pivot pin has been rubbing on the frame. I reassemble the gun and it works fine for about 50 or so rounds and it happens again. And again, and again.

The only thing I can find is the rub mark from the hand pivot pin is getting slightly worse I put a 0.001 shim in place to pull it back from the frame rather than changing the part. If it stops I'll pull the shim and alter the part but I wanted to test first. I doubt this is the issue because the "catch" is occurring at the very beginning of the trigger press.

The rubbing stops but the binding continues to appear after a number of triggering, I'm only dry firing at this point. I've swapped springs covering pretty much all combos with no change.

It's as if something is loose and moving around and getting stuck. Ruger DAs are so much more straightforward!

The only thing I've done other than springs and messing with the strain screw is to polish the frame and rebound spring slide contact points as well as a small area on the frame that was leaving a faint scratch on the hammer just under the top edge of the frame. While not visible on the assemble gun it was causing a minute amount of drag on the hammer.

Any suggestions? I'm at a loss.

Thanks.

PS, I had the "opportunity" to learn how to reinsert the hand spring after it launched on one disassembly, now that's a lesson I really didn't want to learn! What a pain that was.

 

[Lesliet]

When I run into issues like this, I mostly spend a lot of time observing what happens as I move the mechanism, and eventually I figure it out. ( usually just after getting completely frustrated and starting to question my life choices) . Just a thought this morning, but it might be worthwhile to swing the cylinder out, hold the release to the rear, and cycle the trigger, to see if the grittiness is still there, as a means to rule out cylinder related issues, like grit under the extractor. As I recall, the cylinder lock is the first thing that moves, in front of the trigger. The other flag that pops up in my mind is the hand having come apart, and the spring being reinstalled. Is that for sure all in the correct positions? Could the hand have gotten bent a bit?
On mine, I had a bit of something similar to what you're describing with the rough feeling in the very first mm or two of trigger movement, which went away after shimming the trigger so it couldn't rub the sides. Just a few ideas to try, I'd definitely start with ruling out the cylinder, though. Too bad you're not close by, I'd say bring it over for a look.

 

[DLS]

Thanks @Lesliet, other than checking on the cylinder as you mentioned above I haven't had a chance to look at the gun since last week. The cylinder is not the culprit.

I can relate to questioning my life's choices when stuff like this happens, it happens far too often to me .

I'm sure it's either the cylinder lock or something related to the trigger / DA hammer dog interface as the "hitch" is right at the beginning of DA trigger movement, and the "snap over" happens after a tiny amount of rearward motion. So I'll focus my attention there. Further causing me to think it's there is that the SA mode functions perfectly in all respects. So, when thumbing the hammer back, you by pass the dog / hammer interface, so if the problem is there it won't show itself in SA mode.

I'll also look at the hand and spring. There is only one way the spring goes in, and I've found a few good pictures on the net showing the proper installation so I know it's in correctly. There are two pins on the hand, one is the pivot pin and the other rides in an arc shaped groove an limits fore and aft movement. That other pin is smaller in diameter and not quite parallel to the pivot pin. In my mind it should be parallel but it seems to function properly as it is and I have not been able to find a photo that shows the pin arrangement enough for me to be sure.

Sitting in my mailbox is a newly delivered copy of Jerry Kuhnhausen's S&W shop manual so I'll be digging through that over the next few days and hopefully finding something useful there. I have his service rifle manual and it's a great resource, especially the diagrams and photos.

The S&W Revolvers: a Shop Manual, New Expanded 5th Edition: Jerry Kuhnhausen: 0798304326055: Amazon.com: Books

The thing that is really baffling me is that after reassembly the problem is absent, but reoccurs after a number of DA trigger actuations.

Gremlins ... it must be gremlins I say!

Thanks for the tips and keeping us abreast of your H&R fiddling!

Happy New Year!

 

[Lesliet]

And happy New Year to you, as well! The Kuhnhausen book is amazing, best gun book I own. You're probably right, that it's in the cylinder lock, or maybe the little spring for it. One other small thought: pull the guide pin and spring out of the rebound slide, and look at them. Same for the bolt, there's a little pin and spring in there as well, that can be a bit fiddly, watch out for launching them!

 

[DLS]

I didn't do anything to the cylinder lock so if that is the cause at least I'm not to blame .

I have the both the Brownell's and the Gunsmither's rebound slide tools. The Gunsmither's tool is very much worth it. I already had the Brownell's tool since it's perfect from depressing the trigger group latch on Ruger DAs, but it only really helps in taking the rebound slide out on the S&W.

After the first tear down of this Smith, I immediately put the Gunsmither tool on order. I ordered it on a Sunday evening and received it the following Wednesday. I have several of his 10/22 tools and they all work great and arrived quickly.


The Gunsmither tool works like the Brownells tool when removing the slide, but the other end has a handy tool to compress the spring and slip the slide back into place behind the pin. It works a ton better than using the Brownells tool or a ball point pen like Jerry Michlek does on his videos.

Rebound Slide Tool : BROWNELLS S&W REBOUND SLIDE SPRING TOOL | Brownells

SmithMaster™ - trigger spring tool for S&W® Revolvers (gunsmithertools.com)

If the Kuhnhausen S&W manual is half what his service rifle manual is it will be worth every penny! I've just thumbed through it and feel pretty confident it will be.

I'll pour over it this evening (great way to bring in the new year) especially looking for info on the cylinder lock ... it looks to be a potential problem child with that little spring and all.

Thanks again for the input, I'll keep you posted. And if all else fails, a road-trip to the South sounds like it might be fun (so be careful, I might take you up on your offer to look at it). It would be a long drive, but desperate times you know!!!

 

[Centermass]

Just a few of my own personal observations after 4 S&W DA revo projects.
-Once you get to around the 7lbs DA pull range, Federal primers are the only reliable primer to use. CCIs are prolly the worst in terms of cup hardness/thickness.
-Of the 4 I've done, only 1 worked with the JM kit. The others I had to test various weights of rebound springs to get it to overcome the main spring. In 2, I went with Wolfe main springs and rebounds because I couldn't get the correct feel or reset with the JM kits.
-Most of the revo speed shooters I know buy a few strain screws and file them to fit where they want the mainspring adjusted to. That way its bottomed out like its supposed to be. I tried to loc tight my sons 627 Pro and it would work loose after a few matches. Also, on the subject. The Wolfe main springs will mushroom the factory strain screws eventually. My fix to those issues was to replace the strain screws with a tool grade allen head plug screw and drilled and tapped the frame for locking screws. This setup gives a ton of adjustment, these screws don't mushroom and there is very little chance of it working loose.
-I'm using Apex DA only hammers and extended firing pins in the 3 match guns we currently have. My sons 627 DA pull sits around 5.5 lbs and has run flawlessly with Fed primers for over 5k rounds, my 625 JM is around 6.5 has run flawlessly for about 1k with Fed primers and my sons 617 is around 7.25, its a .22, so its kinda finicky, but seems to run pretty flawlessly on Fed automatch and Aguila SuperExtra. The extended firing pins did help alot with more reliable primer ignition.
-I've seen quite a few worked over S&W wheel guns lose the cylinder lock during matches, especially on the very light DA trigger guns. Mostly due to light springs not quite being able to overcome the dirt/grime build-up in the internals. It doesn't take much when the entire system is running on lightened springs, so keep it clean and inspect often.
Good luck and happy new year to all

 

[Lesliet]

@Centermass, did you observe any issues lightening the trigger on the 617? I shoot pretty regularly in matches with a guy who runs a 617, great shooter. He says his gunsmith told him you couldn't really do anything with the triggers on the 617, which struck me as really odd. So he's running a 10.5 lb da trigger.... Were you able to use an Apex DA only hammer in the 617?

 

[orygun]

I've been interested in lightening up the DA pull on a S&W 60-15. From what little I've read I should stay away from the main spring and change out the rebound spring, because this one is also a carry gun. My lack of DA revolver hand work aside, I'm one that accepts the strain screw securing methods are personal, with me choosing bottomed out AND locktited once testing has been done. It's easy enough to shorten that pin head, or lengthen it (after a mistake!) by using a spent primer. I really don't like to have to keep chasing loose screws. Shoot a Ruger Blackhawk Magnum enough and you'll know what I mean.

This is a very interesting thread and I'm soaking up all of the knowledge and experience you guys are sharing.
Thanks.

 

[Centermass]

Outside of the 929, the 617 was prolly my biggest heada che. The rimfires can be a real bubblegum to dial in...ya wanna get them down to center fire weights, but you really can't. It takes alot of fiddling to get em under 10lbs