How to smooth the action on 640

[MrTrolleyguy]

The following is a quote from jtcarm fm the thread Power Trigger..

and thanks to jtcram!

There's more to smooth than the trigger: hammer, cylinder stop, hand.
For that price, you can get it done by a gunsmith.

Yep I'm with Alec. There's more to smooth than the trigger: hammer, cylinder stop, hand.
For that price, you can get it done by a gunsmith.

You can DIY with about $20 worth of wet/dry sandpaper from the auto parts store, in grits from 400 to 2000, a flat surface to stick the paper to (aka.lapping plate) like 1/4" float glass, granite (you can buy a dead-flat lgranite lapping from woodworking stores for about $30). I use a couple of Corian slabs. Then a small, thin flat surface no more than 1/8"'thick for hard to reach spots. I use an iron from an old hand plane and card scraper for super-tight spots.

Google "Scary Sharp" and you'll find detailed descriptions of honing using sandpaper on a flat surface. I use it to sharpen my woodworking tools without spending a fortune on power sharpening systems or expensive bench stones that won't stay flat. 2000 grit will give a super-smooth, mirror finish.


I'd like a bit more information on the DIY. Are there any really good threads with greater detail or any good YoTube videos*.

I have use hard stone to smoth out my M36 and did a trigger spring replacement with Wolf spring kit. I did not touch the sear. However I would like to improve my new to me 640-3.

*The video I used to guide was S&W Airweight Trigger Job: "The Yoda G Mod" I thought that was the "complete trigger job" Obviously there is more that can be done.

Any additional guidance would be appreciated

[alec.mc]

Start out with a new spring kit like the Jerry M " Bang Inc" Kit, or the wolf reduced power.

get yourself some fine india stones and Arkansas stone.

go over every part that makes contact with metal and smooth it out, dont take off metal, but just smooth it out.

The primer manufacture you use in your ammo will also dictate " how low you can go " with your double action weight, for best results - use Federal when loading.

[hotrod150]

I do a light "duty tune" on all my j-frames, probably about what you did to your M36. I replace the rebound spring with a 13# wolff spring, which has worked well in all of them. I use an arkansas stone to polish the rebound slide and adjacent frame surfaces where it rides. I leave the stock 8-1/2# mainspring in for reliable ignition. I clean and oil the lockworks and reassemble. I've never checked the pull weight but it's relatively light and relatively smooth. I like a bobbed hammer on my Chief Specials, and a narrow smooth trigger.
I don't mess with the hammer/trigger engagement surfaces because they have some pretty close tolerances as far as engagement and angles go, & IMHO it's pretty easy for an amateur like me to goof things up. I've owned a gun or two back in the day which a so-called gunsmith "improved" for me, so I realize how easy it is even for someone with some knowledge to make things worse not better.
I would not advise someone to "go over every part that makes contact with metal" with a stone- even doing so lightly it's possible to goof things up. For example, take a look at the single-action notch on the hammer-- it's pretty easy to go from "not much there" to "not enough there". I prefer to err on the side of caution. If a light tune-up like mine doesn't do the trick, maybe a trip to a S&W-specific gunsmith is in order.

[Jaymo]

I don't touch the sears, either. Way to easy to make a mistake that will require hammer and/or trigger replacement.
I leave that to the pros.

[Jaymo]

Another way to smooth it is:
Shoot a lot.
Clean/lube.
Repeat.
Repeat.
Repeat.
Take pride in your handiwork and cleverness.

[Sebago Son]

For a serious defensive revolver such as what the Centennials and Centennial Magnums were intended, a light touch is recommended. Reliability under all conditions is required and trumps all else.

There is a difference between a "Smooth" trigger and a "Light" trigger. For a carry gun I prefer a slightly heavier DA pull that is predictable, but very smooth.

To "Smooth" the action, any burrs or rough surfaces must be polished out. To me, this is best done by first checking for anything obvious and then dry firing the action many, many times. Most of the current, modern Centennials and Centennial Magnums are MIM guns. The upside is that their very close tolerances and clean post mold surfaces allow for much tighter fitting parts that require less “tuning”. Usually these guns are very smooth once the actions are broken in by lubricating well and then dry firing extensively. A very mild lapping compound may speed this process somewhat, but care should be taken. In the past I’ve used toothpaste with good result. Go slow and be sure remove any abrasive media once the wear-in process is complete. It's also smart to use snap caps to protect the firing pin. It may not be absolutely necessary, but it doesn't hurt either and why take the chance?

For the purposes of DA shooting only, a spring kit should be all that is required to reduce the DA trigger pull to "Lighten" the perceived required trigger tension. On J-frames, I usually take this in steps, replacing the Trigger Rebound Spring first and then checking the work. If this is satisfactory, I go no further. If not, then I replace both the Main Spring and the Trigger Rebound Spring from the same kit to maintain the balance of the action. I rarely “shorten” Rebound Springs and NEVER shorten Main Springs. This ill-advised procedure can make the action “wobble” or reduce ignition reliability.

Again I would stress that in any gun you are going to use for serious purposes reliability is paramount and a light touch for any modifications is the wisest path.

[colt_saa]

Spring changes do not alter how smooth an action is, just how heavy.

Smooth is incredibly easy. . . .Pull the trigger 100-200 times each night while watching the news.

If in 30 days you are not pleased with how smooth the action is, then think about spending money one it.

[Malysh]

I had two different M 640s. One was a very early one with the CEN serial number prefix and "tested for +P+" etched into the frame in the bottom of the cylinder window.

Everybody's taste is different but I found the stock actions were excellent just the way they came from the factory.

I also agree, shoot a few hundred rounds from a DA/SA revolver and one will be surprised how smooth the action becomes.

[Jaymo]

The weight of a Smith revolver trigger isn't a deal breaker for me.
I'd rather have smooth than light.
The Colt All American 2000 9mm had a heavy, but slick trigger-cocking only pull. Heavier than I like, but really smooth.

Smith revolvers definitely need to be worn in. Shoot them/dry fire them a lot. Clean and re-lube.
You'd be amazed at how nice they get after you shoot them a good bit.

It's pretty easy to tell a "used" Smith revolver that isn't really used.
You know the ones. They sat in panty drawers and sock drawers and holsters for many years with very few rounds ever put through them.

They have a bit of grittiness to the triggers, which makes them feel rougher and heavier than they should.
They need to be thoroughly cleaned and properly lubed.
Then, they need to be shot, to allow the internals to lap to each other.

The biggest thing I've noticed on mine has been during the first 1/4" of trigger travel. When the front of the trigger cams over the cylinder stop. That needs some smoothing. The rest usually feels pretty darned good to me.
I'll replace the rebound slide spring, but not the hammer spring.
I want the hammer nose to smack primers with authority.

The fun way to improve the trigger pull is:
Shoot/repeat/grin happily.

[Malysh]

Originally Posted by Jaymo

The Colt All American 2000 9mm had a heavy, but slick trigger-cocking only pull. Heavier than I like, but really smooth.

It just proves that everybody has their own taste.
We used to call the Colt 2000 the "Black and Decker" at the gun shop because of it's trigger.

No offense intended but you're the only person I've run across that seemed to like that trigger, and I'm a Colt collector.

[WC145]

I'm happy to pay a gunsmith for action work, I use the same guy for almost all my gunsmithing needs. I tell him what I want, he makes it happen, I pay him, everyone is happy and I don't have to worry about screwing anything up. My "formula" for my DA revolvers is for them to be made DAO, the pull smoothed and lightened, and a trigger stop installed. The cost is less than $100, the result has been excellent every time.

[colt_saa]

Originally Posted by Malysh

It just proves that everybody has their own taste.
We used to call the Colt 2000 the "Black and Decker" at the gun shop because of it's trigger.

No offense intended but you're the only person I've run across that seemed to like that trigger, and I'm a Colt collector.

I do not see in his statement where he says he likes the trigger. BTW no offense intended, but what does being a Colt Collector have to do with liking a trigger or not or even knowing people that like a particular firearm?

The AA2000 was a long stroke DAO design. It was a straight pull much like the HK VP70. What made the AA2000 unique and VERY SMOOTH is that there were roller bearings between the trigger and the frame.

Truth is, we do not even know if you guys are talking about the same action. The AA2000 was original released with a solid trigger but was changed to an articulating trigger design sometime during production.

I still have my AA2000. Truthfully I am a Colt collector from a family of Colt collectors. Two of my uncles owned serial numbers when Colt still did that. So I have many Colts with their two serial numbers in addition to those that I have added myself.

[Dale53]

One thing that I have never seen mentioned when discussing revolver actions:

It is amazing how much smoother an action feels after the shooter gets his hands conditioned to shooting double action. I even suspect that much of the perceived "smoothness" is as a result of the hand conditioning after pulling that trigger thousands of times while "smoothing the trigger".

In my own case, my personal preference these days, is to replace both springs with a Jerry Miculek matched spring set (Bang, Inc) and I set the double action at 9.0 lbs. and the single action to 3.0 lbs. Of course, my daily carry (a Smith 642) is double action, only and it has the original action - reliability for my daily carry is PARAMOUNT. I find I can shoot it well as long as I stay in "condition" by doing a considerable amount of double action work. My days at PPC (back in the day) do me in good stead.

FWIW
Dale53

[snubbyfan]

I like revolvers, my daily carry gun is a 442. Due to degenerative peripheral neuropathy I had to do something. I couldn't pull the trigger without moving off target. I installed an 11 pound Wolff rebound spring and an 8 pound Wolff mainspring. While I had it apart, I smoothed the innards a little with an extra fine Arkansas oil stone. Didn't take much it was pretty smooth already. Cleaned it, oiled it and shot it.
I was very much pleased with the results from my last range trip.

That was firing quickly with a 2 hand hold. Works for me.

[Rick_A]

If it's a carry gun I don't touch the springs.

Practice and use tends to smooth out both the shooter and the gun.

[kaaskop49]

Degenerative peripheral neuropathy...

The only multisyllabic word I use is 'delicatessen.'

Best, as always, to my J-buddy!

Kaaskop49
J-hound extraordinaire

[snubbyfan]

Originally Posted by kaaskop49

Degenerative peripheral neuropathy...

The only multisyllabic word I use is 'delicatessen.'

Best, as always, to my J-buddy!

Kaaskop49
J-hound extraordinaire

And multisyllabic.

My condition's a part of my life and I find myself coming up with ways to compensate for it.

[Malysh]

Originally Posted by colt_saa

I do not see in his statement where he says he likes the trigger. BTW no offense intended, but what does being a Colt Collector have to do with liking a trigger or not or even knowing people that like a particular firearm?

The AA2000 was a long stroke DAO design. It was a straight pull much like the HK VP70. What made the AA2000 unique and VERY SMOOTH is that there were roller bearings between the trigger and the frame.

Truth is, we do not even know if you guys are talking about the same action. The AA2000 was original released with a solid trigger but was changed to an articulating trigger design sometime during production.

I still have my AA2000. Truthfully I am a Colt collector from a family of Colt collectors. Two of my uncles owned serial numbers when Colt still did that. So I have many Colts with their two serial numbers in addition to those that I have added myself.

I've been a Colt collector for quite a long time. The model I was referring to is the AA2000.
I have personally shot 3 of them when they were a new model.
I have to say that although this pistol had it's fans, I can tell you that very few of the Colt Forum members who have experience shooting this discontinued model liked that trigger pull. I haven't found one person on the Colt Forum who did like the trigger, thinking about it a bit more.
Judging from your quote of my post and your reply, it appears I have ruffled your feathers. I apologize, it was not my intent.

However, to the great majority of us, it will remain the "Black and Decker" due to it's unique trigger pull.

'Nuff said. Have a great one!

Sincerely,
Mike

[Jaymo]

Mike,
You're absolutely right. I don't "like" it, but it is smooth.
At least, the few I've handled were.
More guns should have triggers that smooth.
The LGS has one for sale. They want $424 for it. I'm tempted to see what they'll take for it and get it.
If the AA2000 had a pull about half as heavy as it has, I'd love it.

I'd love to have it.
I'd shoot it just to strengthen my trigger finger.

You have to admit, a J frame trigger would feel like a "thought trigger" after putting a thousand rounds through the AA200.

It was the straight pull trigger. Not articulated. Heavy as hell, but smooth as a baby's butt.
I forget whether it's the beer can or Tupperware frame version.

It'd be a great training aid. Not only would it strengthen the trigger finger, it would teach great trigger control. If you jerk that one, it's REALLY going to show.

The way you prepare your trigger finger to shoot the AA2000 is: Pick up ship anchors or blacksmith's anvils with your trigger finger. After a few thousand times, you're ready to shoot the AA2000.

[702bdr]

Here is a great tool I found after I struggled working on my S&W 642.

YouTube

Joe Beary, the inventor of this tool, also gave me this tip for replacing the hammer spring. "Use a kitchen fork to compress the mainspring to insert the capture pin (paper clip?). Place the fork over the plastic ball, and push down with two fingers on the fork, then insert the paper clip to capture the ball and spring, then insert into the revolver."

[BigBill]

I lube the action with moly and run the snots out of it while watching tv.

[jtcarm]

Someone is quoting me

There’s lots of info on DIY action smoothing. I started out with a video by Jerry Miculek.

Aside from the wet/dry paper I mentioned, I use an India stone to break hard edges. About anothe $10 maybe.

I guess you don’t have to worry about it on a 640, but never touch the single action sear.

Since that’s pretty much a carry gun, I don’t know if you want to change any springs.


Norton India Sharpening Stone Square 6 x 1/2 x 1/2 - MPN: 61463686110

[jtcarm]

Originally Posted by Jaymo

I don't touch the sears, either. Way to easy to make a mistake that will require hammer and/or trigger replacement.
I leave that to the pros.

It’s ok to smooth the DA sears, in fact it may require a tiny bit of stoning to get the surfaces squared to each other.

The gotcha is changing the angle, or taking too much off of, the hammer sear.

I’ve never worked a J-frame before, but DA MIM hammer sears are cheap and no big deal to replace if you mess one up.

I suggest this as a good starting point. The video is pre-MIM, but everything’s pretty much the same.

Gun Video Trigger Job: Complete Action Tuning S&W - MPN: X0201D

[CH4]

My 640-1 came with a gritty trigger, especially on rebound. My mechanic found and removed 3-4 large burrs. As mentioned above, shooting it is the best way to smooth a trigger. Oftentimes, I dry fire it incessantly while watching Clint Eastwood, John Wayne or similar testosterone laden movies. Drives my dog bananas.

[shouldazagged]

Originally Posted by Malysh

I had two different M 640s. One was a very early one with the CEN serial number prefix and "tested for +P+" etched into the frame in the bottom of the cylinder window.

Everybody's taste is different but I found the stock actions were excellent just the way they came from the factory.

I also agree, shoot a few hundred rounds from a DA/SA revolver and one will be surprised how smooth the action becomes.

I've carried one of the CEN-prefix 640's for eighteen years. The action was stock, but I had a smith do a very light polish of the innards. It was fine before and better after. Still a fairly heavy pull, but that's what I want in a gun designed for quick, up-close self defense. I pray I never have to use it, but I want to be totally sure it will speak its lines if I do.

[RGVshooter]

I own a relatively new 642, it's my EDC. I love it & trust it with my life. I know there's spring kits out there to reduce the trigger pull but IMO, after shooting revolvers for nearly 28 yrs, I don't think the trigger pull is that bad..
But what about just shooting the thing? I would assume that if the general consensus is that J frames aren't the easiest guns to shoot, wouldn't it make sense to shoot the heck out of it and learn to get better? And wouldn't shooting the heck out of it, eventually wear/polish the metal bearing surfaces hence making the action smoother?

[M3Stuart]

My 2 cents: I've done it a couple ways - dry firing a zillion times, and paying for trigger work (I don't do that myself). Both work ok but paying a gunsmith works FASTER!

The only thing I haven't tried yet, but am working on right now, is sending it back to S&W for a PC Action Package. BUT, I'm trying that right now on one of my revolvers. I'll tell you how that works out in 3 or 4 months when I get it back.