jdickson397
Member
I recently purchased a S&W 625 Performance Center revolver. It has a smooth trigger pull but way too heavy especially for DA. I just ordered Jerry Miculek's DVD on trigger jobs. Any advice?
Need advice on DIY trigger job
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badguybuster
Member
You can always put lighter springs in.
Smith357
US Veteran
My only advise is do not touch the engagement surfaces, just swap out the springs for some lighter ones. The old springs can always be put back in, you cant add the metal back to the trigger if you remove too much.
snubbiefan
Member
Ditto what he said!
The springs are relatively easy to change (the rebound being the most troublesome) and will make a big difference. Let the gun-smith that knows what he is doing "work the stoning". You can take it off, but you can't put it back.
The springs are relatively easy to change (the rebound being the most troublesome) and will make a big difference. Let the gun-smith that knows what he is doing "work the stoning". You can take it off, but you can't put it back.
imashooter2
Member
The Miculek video is excellent. My advice is wait for it to arrive, watch it straight through, then watch each step again before performing it.
ETA: The "expert gunsmith" started off as a tyro just like you. Trigger jobs aren't hard.
ETA2: A Performance Center revolver is probably already polished internally. It probably has a bent mainspring and cut rebound spring too. What is your current DA pull weight and what do you expect it to be when you finish?
ETA: The "expert gunsmith" started off as a tyro just like you. Trigger jobs aren't hard.
ETA2: A Performance Center revolver is probably already polished internally. It probably has a bent mainspring and cut rebound spring too. What is your current DA pull weight and what do you expect it to be when you finish?
Last edited:
scooter123
Member
Jerry's DVD will provide an excellent guide to tuning your 625. However, you have to remember that he has access to a warehouse full of parts that you don't, so he can tune his guns to the Nth degree. With that in mind I would suggest that you NOT try an match his results but set your 625 a bit on the conservative side.
Personally, I've experimented with tuning my 620 for a lighter trigger and it now has an 8 lbs. DA trigger that is perfectly reliable with Speer, Winchester, Remington, and Federal ammunitions.
The final recipe was actually pretty simple. I've handmade shims that fit under the strain screw that allowed me to use the factory mainspring and step the tension down as I tested for reliable ignition. Total shim installed currently is 0.022 inch. I've also installed a 13 lbs. rebound spring after smoothing the frame recess and the rebound slide. Finally, I shimed the trigger by 0.002 inch with a handmade shim on the trigger stud because it was rubbing in the frame recess. BTW, diamond burrs and a Dremel make for pretty quick work of shaping shim stock into fitted shims but they are easy to lose if you drop them. I'll also note the rebound spring selected was because I wanted the SA trigger to break as near as 3 lbs. as possible and the 620 is the only gun that needed a 13 lbs spring to achieve this, my 67-1, 610-3 needed 14 lbs. rebound springs to hit this SA target.
I'll also note that I tried a 12 lbs. rebound spring in the 610-3 at one point and while the trigger reset perfectly in testing it locked up the lockwork twice during live fire testing. If you go too light on the rebound spring, do NOT rely on snap caps to test it, shoot it and see what happens then. I'll also note that the lockup was a bit complex, simply pushing the trigger forward didn't free it up. I had to wiggle the hammer slightly while pushing the trigger forward until it "snicked" and freed up. Bottomline, do NOT go under 14 lbs. with the rebound spring until you've fully smoothed the area for the rebound slide and smoothed the slide completely. I suspect that the pushrod on the trigger came unseated from the rebound slide and that's what tied up my lockwork.
The final aspect of tuning the 620 was to install a Cylinder & Slide extended firing pin. This firing pin features both a slightly longer overall lenth as well as a longer travel slot than the factory firing pin. I tried one in my 610-3 when the mainspring was still at full factory power and based on my experience I do not recomend the installation of this firing pin until the DA trigger has been reduced to 9 lbs. or less. With the mainspring at full power the primer strike was hard enough that it fractured a full 30% of the primers, which was quite obvious when I was putting my fired casings back into the ammo trays for storage. Thirty of 100 rounds showed dark primers and microscopic examination of those primers showed that every one had microscopic cracks in the dimples. Now that I've tuned the trigger in the 610-3 to 9 lbs., I've not seen one single dark primer.
Now, some final notes.
During all this experimenting I've been testing both DA and SA shooting. Ammo used for the DA testing was all Speer due to it's reputation for "hard" primers and SA testing was with Amercan Eagle because it's cheaper and easier to find. The SA shooting has been done from a benchrest at 35 yards using a reflex sight. When I first took the 620 to 8.0 lbs. I noticed that my shots were stringing vertically. At first I thought this was due to variation in the cheap American Eagle ammo I was shooting for the SA testing. However, after doing a bit of fishing on the Net I found that primers can suffer from incomplete ignition with a "marginal" strike. Meaning, it may go bang but it's a fizzy bang that doesn't ignite the powder well. The result is vertical stringing due to incomplete ignition and varations in velocity. Installing the extended firing pin resolved this issue. BTW, I recently tried the 620 out with a scope mounted at 50 yards and shot a 4 round 7/8 inch group with 3 or the 4 in a 1/2 inch cloverleaf, so I am seeing superb accuracy after all this tuning.
Second, my reading on the net also has led me to believe that Primer Ignition is the result of the transfer of Kinetic Energy and NOT Momentum. If you remember your high school Physics, Kenetic Energy is a result of Velocity Squared times the Mass, Momemtum is Velocity times Mass. This means that a lighter hammer moving faster will produce a more complete primer ignition cycle than a heavier hammer moving slower. Basically, I believe that you can tune a gun equipped with a Service hammer lighter than you can tune a gun with the wider Target hammer. It also means that a Bobbed hammer can be tuned lighter than a Service hammer. Yeah, this does go against intuition, however it is quite predictable if you have any familiarity with Newtonian Physics and I believe this to be true. Quite simply, lighter hammers allow you to tune for a lighter DA trigger pull. In addition, a lighter hammer will produce a faster "lock time" which can matter when you are shooting for pinpoint accuracy at long range.
BTW, this knowledge has me constantly doing "thought" experiments about how to construct a Carbon Fibre or Titanium superlight hammer, unfortunately I have not yet had any success in figuring out how to bond a steel sear to either Carbon Fibre or Titanium. One of these days I may actually order up some Titanium and use the CnC gear at work to make a DA only hammer for the 620 out of that light material just to see how light a DA trigger can go with a superlight hammer. I have a sneaking hunch that with a needle bearing pivot, a 3 lbs. DA trigger just might be possible.
Bottomline, you can get a much better trigger, all it takes is a bit of work and a bit of experimenting. If you really want to push the limits, I would recomend that you purchase a Lyman digitial trigger gage, they are much easier to use than a spring gage and allow you to proceed in small increments. I'd also suggest that you plan on doing lots of reliability testing to insure good function and accuracy. If you don't want to push the limits, throw in a 14 lbs. rebound spring, tune the DA trigger to 9 lbs. even, add either a C&S or Apex Tactical extended firing pin and call it good.
Personally, I've experimented with tuning my 620 for a lighter trigger and it now has an 8 lbs. DA trigger that is perfectly reliable with Speer, Winchester, Remington, and Federal ammunitions.
The final recipe was actually pretty simple. I've handmade shims that fit under the strain screw that allowed me to use the factory mainspring and step the tension down as I tested for reliable ignition. Total shim installed currently is 0.022 inch. I've also installed a 13 lbs. rebound spring after smoothing the frame recess and the rebound slide. Finally, I shimed the trigger by 0.002 inch with a handmade shim on the trigger stud because it was rubbing in the frame recess. BTW, diamond burrs and a Dremel make for pretty quick work of shaping shim stock into fitted shims but they are easy to lose if you drop them. I'll also note the rebound spring selected was because I wanted the SA trigger to break as near as 3 lbs. as possible and the 620 is the only gun that needed a 13 lbs spring to achieve this, my 67-1, 610-3 needed 14 lbs. rebound springs to hit this SA target.
I'll also note that I tried a 12 lbs. rebound spring in the 610-3 at one point and while the trigger reset perfectly in testing it locked up the lockwork twice during live fire testing. If you go too light on the rebound spring, do NOT rely on snap caps to test it, shoot it and see what happens then. I'll also note that the lockup was a bit complex, simply pushing the trigger forward didn't free it up. I had to wiggle the hammer slightly while pushing the trigger forward until it "snicked" and freed up. Bottomline, do NOT go under 14 lbs. with the rebound spring until you've fully smoothed the area for the rebound slide and smoothed the slide completely. I suspect that the pushrod on the trigger came unseated from the rebound slide and that's what tied up my lockwork.
The final aspect of tuning the 620 was to install a Cylinder & Slide extended firing pin. This firing pin features both a slightly longer overall lenth as well as a longer travel slot than the factory firing pin. I tried one in my 610-3 when the mainspring was still at full factory power and based on my experience I do not recomend the installation of this firing pin until the DA trigger has been reduced to 9 lbs. or less. With the mainspring at full power the primer strike was hard enough that it fractured a full 30% of the primers, which was quite obvious when I was putting my fired casings back into the ammo trays for storage. Thirty of 100 rounds showed dark primers and microscopic examination of those primers showed that every one had microscopic cracks in the dimples. Now that I've tuned the trigger in the 610-3 to 9 lbs., I've not seen one single dark primer.
Now, some final notes.
During all this experimenting I've been testing both DA and SA shooting. Ammo used for the DA testing was all Speer due to it's reputation for "hard" primers and SA testing was with Amercan Eagle because it's cheaper and easier to find. The SA shooting has been done from a benchrest at 35 yards using a reflex sight. When I first took the 620 to 8.0 lbs. I noticed that my shots were stringing vertically. At first I thought this was due to variation in the cheap American Eagle ammo I was shooting for the SA testing. However, after doing a bit of fishing on the Net I found that primers can suffer from incomplete ignition with a "marginal" strike. Meaning, it may go bang but it's a fizzy bang that doesn't ignite the powder well. The result is vertical stringing due to incomplete ignition and varations in velocity. Installing the extended firing pin resolved this issue. BTW, I recently tried the 620 out with a scope mounted at 50 yards and shot a 4 round 7/8 inch group with 3 or the 4 in a 1/2 inch cloverleaf, so I am seeing superb accuracy after all this tuning.
Second, my reading on the net also has led me to believe that Primer Ignition is the result of the transfer of Kinetic Energy and NOT Momentum. If you remember your high school Physics, Kenetic Energy is a result of Velocity Squared times the Mass, Momemtum is Velocity times Mass. This means that a lighter hammer moving faster will produce a more complete primer ignition cycle than a heavier hammer moving slower. Basically, I believe that you can tune a gun equipped with a Service hammer lighter than you can tune a gun with the wider Target hammer. It also means that a Bobbed hammer can be tuned lighter than a Service hammer. Yeah, this does go against intuition, however it is quite predictable if you have any familiarity with Newtonian Physics and I believe this to be true. Quite simply, lighter hammers allow you to tune for a lighter DA trigger pull. In addition, a lighter hammer will produce a faster "lock time" which can matter when you are shooting for pinpoint accuracy at long range.
BTW, this knowledge has me constantly doing "thought" experiments about how to construct a Carbon Fibre or Titanium superlight hammer, unfortunately I have not yet had any success in figuring out how to bond a steel sear to either Carbon Fibre or Titanium. One of these days I may actually order up some Titanium and use the CnC gear at work to make a DA only hammer for the 620 out of that light material just to see how light a DA trigger can go with a superlight hammer. I have a sneaking hunch that with a needle bearing pivot, a 3 lbs. DA trigger just might be possible.
Bottomline, you can get a much better trigger, all it takes is a bit of work and a bit of experimenting. If you really want to push the limits, I would recomend that you purchase a Lyman digitial trigger gage, they are much easier to use than a spring gage and allow you to proceed in small increments. I'd also suggest that you plan on doing lots of reliability testing to insure good function and accuracy. If you don't want to push the limits, throw in a 14 lbs. rebound spring, tune the DA trigger to 9 lbs. even, add either a C&S or Apex Tactical extended firing pin and call it good.
David LaPell
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The one thing I will tell you about Jerry's video is that it was done with a pre-lock gun and pre-MIM. A couple of things will be slightly different and I suggest that you watch the video three or four times. Another thing I would say is get the tool from Brownells to get the trigger return spring out which is much better than just a screwdriver. I have done several trigger jobs since I bought the video, although none recently, including a IL lock gun and it does help. I do both the trigger job and the spring kit and all the guns have been lightened up enough to make them smoother. Remember that when you use that stone, you're only smoothing that burrs off the part, not taking off any metal, and it is very easy to go too far, that's why I say watch the video several times. If you can, watch the video while you are doing your first attempt so you can go over it as you see it. Very helpful.
earplug
Member
Order a couple of mainsprings, rebound springs and strain screws before you get started. Then you can mess with them and have a handy spare. I have used heat treated set screws from the hardware store to replace strain screws. I think its a 8x32? I had to grind the heads down to fit the frame.
A small bench vice is real nice to hold parts while working on them.
If you don't have a decent set of stones get them. A rebound slide tool is real nice to have.
All the 625's I've owned needed a bigger radius on the chambers to allow easy loading while shooting USPSA or ICORE. That's another bit of gunsmithing you might want to consider.
I have my guns set up to shoot Federal primers only. I lightened the hammers and it does make a difference. I kept one hammer spur on my bullseye gun, but used a carbide burr to hollow out and remove metal from the hammer. You will have more respect for MIM parts after doing this job. The lock does not work after doing this work. So I took them off.
I believe the faster lighter hammer helps my SA shooting for bullseye.
I tried the C&S firing pin and as the direstions say it will break if you dry fire the gun. I went back to the S&W part and all is good.
Midway is a good source of parts if you mess up something or the little spring under the DA sear goes away. The new model stirrup can fall off and go missing if your used to the old type.
Its not a hard job. And cheaper then working on cars.
A small bench vice is real nice to hold parts while working on them.
If you don't have a decent set of stones get them. A rebound slide tool is real nice to have.
All the 625's I've owned needed a bigger radius on the chambers to allow easy loading while shooting USPSA or ICORE. That's another bit of gunsmithing you might want to consider.
I have my guns set up to shoot Federal primers only. I lightened the hammers and it does make a difference. I kept one hammer spur on my bullseye gun, but used a carbide burr to hollow out and remove metal from the hammer. You will have more respect for MIM parts after doing this job. The lock does not work after doing this work. So I took them off.
I believe the faster lighter hammer helps my SA shooting for bullseye.
I tried the C&S firing pin and as the direstions say it will break if you dry fire the gun. I went back to the S&W part and all is good.
Midway is a good source of parts if you mess up something or the little spring under the DA sear goes away. The new model stirrup can fall off and go missing if your used to the old type.
Its not a hard job. And cheaper then working on cars.
Sportsterguy
Member
I would suggest applying Militec-1 grease to all of the moving innards that contact each other first. Fire/cycle the action and IT WILL smooth out pretty darn fast. I do this, plus apply their lube/conditioner to all of my S&W's internals. Feels like you've done a trigger job right off the bat.
If you are going to attempt this yourself watch the video and make sure you have the right tools and that includes a screwdriver from Brownells that fits the plate screws so you don't bugger them up. I'm semi mechanically inclined (enough to get in trouble
) but would not feel comfortable taking a file to my S&W's.If its a self defense weapon I would not lighten it at all for liability reasons. A more important reason not to lighten it would be a light trigger strike with the "oh ****" coming out of your mouth when the revolver doesn't fire due to a light strike. If its a range revolver take these experienced gents advice and buy ya a Wolff spring kit to lighten it up. JMHO.
Good luck.
Last edited:
chp
Member
The Wolff reduced main spring is excellent and sets off all rounds I've ever shot with it.
OP
jdickson397
Member
Thanks to all of you. Will let you know the results in a week or so.
OP
jdickson397
Member
UPDATE REPORT: Well, I received the Jerry Miculek reduced power competition spring set from Brownells. As was suggested to me in several of the replies in this thread the insides of my 625 PC were polished up just fine by S&W so all I did was replace the spring set. It feels great to me now. Thanks to you all.
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