View Full Version : S&W 629 - SA pull seems TOO light
July 14, 2009, 07:49 AM
I picked up a S&W 629 that was used. It appears that the previous owner (an unknown entity - this was an estate sale) has had the trigger pull lightened. The DA pull is very smooth and is quite nice. I don't have a trigger scale, so I don't know how much but I like it. The SA pull is another story. It is a little too light. I can place my finger on the trigger, but if I pull ever so slightly it's going to fire. This is set up perfectly for target shooting (what I'm thinking the original owner must have been into) but won't work as well with my needs (woods gun).
Now, with my limited knowledge of S&W internal workings, I'm thinking that either of two things have happend. Since the mainspring tension screw is in good and tight and neither the mainspring nor the screw appear to be aftermarket, the remaining suspects are either the rebound spring or that the seer engagment surfaces have been honed. If it is the former, then it would be easy to fix. If it is the latter, then it is probably beyond my ability to fix (other than replacing the internal parts with factory originals from Numrich).
1. Is there any way to tell if the rebound spring is not factory?
2. Is there an easy way to tell if somebody has been honing the engagement surfaces?
July 14, 2009, 03:15 PM
It seems to me that a woods gun with a light SA pull wouldn't be a problem. If you're hunting it makes for a more accurate shot, if you're defending yourself you would normally use DA anyway. I've got an old S&W 1955 Target (Pre-model 25) with a similar trigger and it's one of my favorites.
The only concern would be "Push Off". With the hammer cocked, apply quite a bit of pressure to the hammer with your thumb. If the hammer drops, it's likely to have been stoned to the wrong angle by someone and needs to be repaired.
July 14, 2009, 04:38 PM
I have DA revolvers that have light SA trigger pulls (2lb.), when the DA pull is still within S&W specs.
S&W spec for DA pull is about 3lb. tension on the hammer with trigger pulled. Use the gage to just move the hammer back slightly, and measure that. 2.8 lb will probably provide enough force for reliable ignition, but less than spec.
DA trigger pull might be from 8 to 10 lb. or so, and is affected by the the power of both the main and rebound springs. The hammer force is not affected by the rebound spring.
The SINGLE action pull, unlike the DA pull, is probably more closely related to hammer sear engagement set at the factory--a delicate operation for the gunsmith. Don't think MIM technology eliminates the need for a smithie at the factory to make the proper fit.
Not saying the power of the mainspring has no effect, but I am saying that you can't fix it with heavier springs, since light SA pulls are found on revolvers with heavy main and rebound springs that produce heavy DA pulls--- right out of the factory.
I just live with mine, since they're combat guns used DA, anyway.
SA pulls seems to vary anywhere from 2 lb. (maybe less) to about 5 lb. A serious consideration for those untrained enough to be cocking revolvers under combat conditons.
To paraphrase: Forget the rebound spr.. I'ts affect would be even less than the small to moderate affect of the mainspring. You can't fix that, and there are few smiths I'd trust to do it, and you're probably talking new parts.
A great gunsmith, who I do trust to work on my revolvers, explained the delicate nature of mating the SA notch of the hammer with the sear. He also thinks highly of the gunsmiths who for for S&W.
July 14, 2009, 05:33 PM
Thanks guys. I'm going to do some shooting this weekend and see if it bothers me in a simulated hunting scenario.
July 14, 2009, 07:42 PM
The single action pull on S&W revolvers have always been extremely light. It has nothing to do with the springs. The springs only affect double action pull. It's because the hammer cocking notch for single action is only a couple of thousandths of an inch tall. It's supposed to be that way. All trigger work on S&Ws is done only to the double action. I've never seen one that needed work on the single action. If it's too light for you learn to shoot it double action or trade it for a Ruger. Sounds like you've never encountered a nice trigger before.
July 14, 2009, 08:41 PM
Sounds like you've never encountered a nice trigger before.
You're right. I've always owned Rugers. :D
July 15, 2009, 10:17 AM
When I purchased my used 629 all functions were smooth and flawless. Best function was the trigger in SA: very light. When compared to my Rugers and other S&W revolvers it seemed too good to be true. Then I discovered that with each successive range period the trigger was becoming way too sensitive. With an empty cylinder and finger out of the trigger guard I lightly rapped the cocked pistol with my palm and the hammer fell. Repeated this action several times. An unsafe situation.
Disassembed the action and discovered that the contact point of hammer and trigger had been altered resulting in a very narrow contact area. A new hammer and trigger solved the unsafe situation yet retained the smooth SA trigger function.
Whenever I check out any firearm, especially revolvers and semi pistols, I cock the hammer and give it a good smack.
July 15, 2009, 10:53 AM
As long as you can tell that you touched the trigger before it went off, there's no such thing as "too light". ;):)
July 15, 2009, 11:27 AM
I have the 629 that I bought new and the SA is one of the lightest in my revolvers. I like it though you better make sure you practice all the safety rules when you are using the SA, keep the the barrel down range.
It can appear extremely light after you have fired a few DA rounds.
July 15, 2009, 12:25 PM
A new hammer and trigger solved the unsafe situation yet retained the smooth SA trigger function.
Let me assume the worst case scenario for a second. A replacement hammer and trigger are available from Numrich for a relatively small cost. Are these parts ready to work as drop-ins or will they require some custom stoning to get them matched up right?
July 15, 2009, 02:37 PM
The answer to your question is a very light stoning on the new parts. Enough to see a polish but not enough to ruin the case hardening and certainly not enough to alter the hammer/trigger interface angle. I believe the previous owner may have been over zealous with a stone or file and that was the cause of the dangerously oversensitive trigger.
Initially I thought it was my fault because with all my Smiths and Rugers I lightly polish those contact surfaces to get a smooth trigger. Apparently the 629 had been altered before.
July 16, 2009, 09:02 PM
Well, I took it out and put a dozen rounds through it today. It's light, but not unsafe. If I go to shoot a deer or hog and get excited, I could wind up with a premature shot. I'll just have to remember to keep my trigger finger on the guard until I'm lined up.
July 17, 2009, 08:43 PM
I checked my Model 28 with my RCBS gage, and the single action broke at 2lbs, 9 ozs. I have lightly polished the contact surfaces on the SA sear, and trigger notch. Just a couple of light strokes with a fine stone. Remember when you apply a coating of oil to these surfaces, it will be even lighter. I haven't checked the DA pull, but it is nice and easy, and I have never had a misfire in this gun.
July 17, 2009, 10:28 PM
See if you can find a trigger pull gauge; an S&W revolver SA pull will run about 2 3/4 pounds. Anything much under that, or if the trigger tries to return after release, signals danger.
Note, that to many folks, especially those used to something like a trapdoor Springfield, 2 3/4 pounds feels like a "hair" trigger, so it is best to get the gauge into the act for an objective test.
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