S&W 929 Trigger Adjustments

[Dirt Merchant]

Being so damn cold out, I decided to give that rebound bar mod a go. Figured, worst case I'd be ordering a replacement from Brownells.

I was running a 14lb spring 'cause I wasn't getting reliable trigger resets with 13lb. Even 14lb at the start would not reset the trigger 100% if I released it really really slowly but it's broken in now and resets 100% with the 14lb spring. With 13lb, it definitely was not reliable. So today I did that mod VanMan pointed out and knocked off the corner of the rebound bar. I didn't remove a lot of material. I may go back in and remove just a hair more. I polished the areas and reassembled with the 14lb spring. That harsh trigger reset is a bit muted now and feels a lot better.

I replaced the 14lb spring with the 13lb and trigger felt smoother, a little lighter as to be expected and reset was 100%. VanMan was on the money. With the 14lb spring, DA trigger pull was avg 6.5lbs, now it's 5.5lbs with the 13lb. SA went from 2.4lbs with the 14lb spring to 2.1lbs with the 13lb.

After my slicking up job, the trigger felt pretty good but now, it's even nicer. Thanks VanMan!

I forgot to take pics of the after it was modded. Next time I crack it open, I'll take a pic.

Here's my slicking up thread:
https://www.canadiangunnutz.com/for...-up-a-Smith-amp-Wesson-686?highlight=slicking

Nice work! Are you still using the Reduced Power Wolff main spring? I am still struggling with getting a good strike with mine (DA: 7 - 2oz). I also ground down my strain screw to add to the list of variables. Are all S&W strain screws the same length? I ordered a couple more but they will not be here til next week. In the mean time, I cut up a couple of 8-32 bolts but I am not exactly sure how long to make them.
I guess I will try more polishing. Thanks for posting your slicking up thread. Its always good to have some detailed images of what you are working on. What do you use as a buffing compound? I have actual buffing compound for a shop 10" buffer wheel that I can put on a cone shaped 1/2" padded tip on a dremel or is it better to use Flitz with the dremel cone tip? I was also wondering if there was any point to taking out the S&W built in trigger lock there is a little bit of a post that looks like it rides in a guide way, in the hammer?

 

[Trinimon]

Nice work! Are you still using the Reduced Power Wolff main spring? I am still struggling with getting a good strike with mine (DA: 7 - 2oz). I also ground down my strain screw to add to the list of variables. Are all S&W strain screws the same length? I ordered a couple more but they will not be here til next week. In the mean time, I cut up a couple of 8-32 bolts but I am not exactly sure how long to make them.
I guess I will try more polishing. Thanks for posting your slicking up thread. Its always good to have some detailed images of what you are working on. What do you use as a buffing compound? I have actual buffing compound for a shop 10" buffer wheel that I can put on a cone shaped 1/2" padded tip on a dremel or is it better to use Flitz with the dremel cone tip? I was also wondering if there was any point to taking out the S&W built in trigger lock there is a little bit of a post that looks like it rides in a guide way, in the hammer?

Thanks. Yes, I'm using the Wolff RP mainspring. I did read a few reviews that said the Wolff and the JM RP springs resulted in light primer strikes. So far, I'm popping CCI primers without any failures BUT I purposefully didn't seat some test shells fully to see if they would pop and they did not, even with a second strike. I did shoot the pistol after my initial slicking up and spring change last summer and ran approx 75rnds through it without any light primer strikes. I used mostly CCI but added a few S&B primers for live testing. I didn't muck with the strain screw because I knew I needed as much spring power form that RP spring. Yesterday I did mod the mainspring a little to help increase the weight a fraction more. Did the pencil test (cocked hammer, dropped in a pencil; eraser side to firing pin) before and after and noted the pencil was jumping up a fraction higher so I think I'm good to go.

Today I took the revolver apart again (I just got to tinker, can't leave well alone) and knocked down the corner a fraction more and the harsh "clunk" reset you normally feel is much less pronounced. I think this is as good as it's gonna get for now.

It looks slightly rounded in the pic but it really isn't. It's not a critical sear part anyway.

I'm tempted to pick up one of those keyhole plugs to get rid of the locking mechanism. I'm not sure if it'll make things smoother but right now, it's pretty slick.

I also have a benchtop grinder/buffing wheel but it's not that useful for these small parts. A Dremel with a large wheel, small wheel and cone felt pads, the rubber polishing bits and some Fitz polish is all I used. For the sears etc I carefully use fine stones to just knock off the burrs or chatter without altering the engagement angles.

Also made up my own tool for reinstalling the rebound bar. I grabbed an old 3/64" drill bit and cut a slot in the stem using a Dremel with a cut-off wheel, fine tuned the width with some mini files. Chucked the bit in a drill and used some 200grit emery paper to knock off a few thousand off the diameter, ground the bit's butt flat and left unpolished for added grip texture to prevent slipping, then polished the stem with some 600grit emery. Of course you can do the ballpoint pen trick or use screwdriver but you risk stabbing yourself (been there!) or order the tool from Brownells.

 

[VanMan]

Great work Trinimon!

 

[Dirt Merchant]

Thanks. Yes, I'm using the Wolff RP mainspring. I did read a few reviews that said the Wolff and the JM RP springs resulted in light primer strikes. So far, I'm popping CCI primers without any failures BUT I purposefully didn't seat some test shells fully to see if they would pop and they did not, even with a second strike. I did shoot the pistol after my initial slicking up and spring change last summer and ran approx 75rnds through it without any light primer strikes. I used mostly CCI but added a few S&B primers for live testing. I didn't muck with the strain screw because I knew I needed as much spring power form that RP spring. Yesterday I did mod the mainspring a little to help increase the weight a fraction more. Did the pencil test (cocked hammer, dropped in a pencil; eraser side to firing pin) before and after and noted the pencil was jumping up a fraction higher so I think I'm good to go.

Today I took the revolver apart again (I just got to tinker, can't leave well alone) and knocked down the corner a fraction more and the harsh "clunk" reset you normally feel is much less pronounced. I think this is as good as it's gonna get for now.

It looks slightly rounded in the pic but it really isn't. It's not a critical sear part anyway.

I'm tempted to pick up one of those keyhole plugs to get rid of the locking mechanism. I'm not sure if it'll make things smoother but right now, it's pretty slick.

I also have a benchtop grinder/buffing wheel but it's not that useful for these small parts. A Dremel with a large wheel, small wheel and cone felt pads, the rubber polishing bits and some Fitz polish is all I used. For the sears etc I carefully use fine stones to just knock off the burrs or chatter without altering the engagement angles.

Also made up my own tool for reinstalling the rebound bar. I grabbed an old 3/64" drill bit and cut a slot in the stem using a Dremel with a cut-off wheel, fine tuned the width with some mini files. Chucked the bit in a drill and used some 200grit emery paper to knock off a few thousand off the diameter, ground the bit's butt flat and left unpolished for added grip texture to prevent slipping, then polished the stem with some 600grit emery. Of course you can do the ballpoint pen trick or use screwdriver but you risk stabbing yourself (been there!) or order the tool from Brownells.

I think I have discovered your secret! Are you using a 617 rebound slide in 929? I still must be missing something significant as even at a 7 lbs 4 oz pull, I was still only getting 75% of the American Eagle 147 grain rounds to go off today in DA but 95% in SA. Maybe it was my modified stock mainspring that wasn't giving enough snap or i STILL need more polishing but I was able to get 100% ignition with the Wolff RP main spring and a 12 lb rebound spring the last time I was at the range (DA 7 lbs - 10oz). I don't know how you guys are getting such low DA trigger pull weights.... MAGIC!!!!! or is there really something to the 617 rebound slide???

 

[VanMan]

I think I have discovered your secret! Are you using a 617 rebound slide in 929? I still must be missing something significant as even at a 7 lbs 4 oz pull, I was still only getting 75% of the American Eagle 147 grain rounds to go off today in DA but 95% in SA. Maybe it was my modified stock mainspring that wasn't giving enough snap or i STILL need more polishing but I was able to get 100% ignition with the Wolff RP main spring and a 12 lb rebound spring the last time I was at the range (DA 7 lbs - 10oz). I don't know how you guys are getting such low DA trigger pull weights.... MAGIC!!!!! or is there really something to the 617 rebound slide???

I think it may be a combination of the shape you have bent your main spring into, as well as the ground down strain screw. When I initially tried your main trigger, there was that "sproing" feel to it when the hammer fell. That means the hammer was decelerating towards the last half of the hammer fall. If you take a stock main spring and slowly back out the strain screw, you will eventually get that same "sproing" feel to your hammer fall. The bottom part of the "S" bend we talked about is to make sure the main spring is pulling consistently throughout the entire hammer fall. With a filed down strain screw, you would have to tweak that bend a bit to get it to work right.

 

[Dirt Merchant]

I think it may be a combination of the shape you have bent your main spring into, as well as the ground down strain screw. When I initially tried your main trigger, there was that "sproing" feel to it when the hammer fell. That means the hammer was decelerating towards the last half of the hammer fall. If you take a stock main spring and slowly back out the strain screw, you will eventually get that same "sproing" feel to your hammer fall. The bottom part of the "S" bend we talked about is to make sure the main spring is pulling consistently throughout the entire hammer fall. With a filed down strain screw, you would have to tweak that bend a bit to get it to work right.

I hear what you are saying. I have made up several strain screws of various lengths (0.3135", 0.3440" and 0.3535") and several main springs now but seem to either get around well over 9 lbs to 7 lbs 10oz or just under 7 lbs depending on which combination of springs and strain screw I test out. I have ordered a couple of new strain screws and have a couple of untouched Wolff main springs. I might as well start out fresh with the correct length and fresh springs!