Need advice: GP100 Hammer/Main Spring

B

Ben_Snow

New member
Folks--Need some advice--

Purchased a Ruger 357M GP100 MC (4.25") several months ago.. Excellent accuracy with 38SP, something my 357 Blackhawk never shot accurately... Want to start shooting IDPA SSR, so needed to move to a IDPA compliant DA.

Anyhoo -- Didn't care for the trigger pull on the GP100, not terrible by any means, but a lighter pull would be preferable. After some research decided to follow what many others have done, order the Wolff spring kit. I installed the 10lb main and 8lb return spring. Returned to the range and had 3 FTF round out of 100 (38SP w/Bullseye 2.9gr 148 coated BNWC - CCI 500 SPP). Second trip to the range (yesterday), and it went down to 52 FTF out of 100 !! Only difference was the second batch was from a different box of CCI primers (500 SPP).

Decided to take two courses of action:

1. Purchased 1000 Federal Primers to compensate for a lighter spring
2. Decided to install the 12lb main spring to improve reliability.

The Wolff 12lb spring is horrible, it feels stronger than the stock spring??

Now my options are to reinstall the stock spring, or switch back to the 10lb spring and start loading with Federal Primers....

Any input or advice from any other GP owners on how they tackled this issue, if at all?

Thanks !
 
Any time someone swaps out factory springs they're compromising the reliability of the firearm. Firearms are generally made with SAAMI spec ammunition in mind. When you deviate from it, the firearm takes one or more step closer to becoming a prima donna that requires special ammunition or care to operate. It becomes less of a defensive firearm whose priority is to work everytime the trigger is pressed.

At the most, I'd get the trigger worked on (smoothened as opposed to lightened).
 
Gary:

I tend to agree... Perhaps I decided to take the cheap way out instead of having a gunsmith perform their own professional magic. I'm only $12 out for the springs, and I can still use the Federal Primers, so not too deep into this to turn back.

Heard a rumour that Ruger places heavier than needed springs to overcome poor machining/fitting of their parts. That may be just horsecrap, but many of the edges on the hammer and trigger assembly are pretty rough, the hammer has friction scrape marks on one side despite having the hammer shims installed. Was rather disappointed in the quality of the Match Champion, the extra "polishing" that it receives over the stock GP seems to be mostly marketing hype. Don't get me wrong, I still love my GP100, just need a way to smooth things out without braking the bank.
 
Since you've taken yours apart, you may want to look at any burrs and remove them by stoning. Afterward, apply oil and work it in the DA mode with a snap cap (that plastic cylinder insert works well) for 1,000 times (500 each hand). That may help.
 
Do a google search. There are instructions for a tear down and parts polish for the GP and SP guns. There are also youtube videos on ruger tuning. Its easy to do. I have done mine and did one of them way before I had internet. Its pretty obvious what needs to be smoothed up.
 
Because of the mechanics of the gun the Ruger has to transfer the hammer energy to the firing pin through a transfer bar. It takes more spring to do that.
Put the factory springs back in and while you have it apart place some polishing compound on the sear and trigger. assemble the gun and dry fire it until your fingers get tired. Take it back apart and clean the polishing compound off with very hot water and then lubricate with a tiny bit of light oil. Reassemble and check the trigger pull. Repeat the process until there is no gritty feel to the double action trigger. Then get yourself some slow cure epoxy and apply it behind the trigger on the rear of the trigger guard. After it cures for 24 hours sand it to the point the gun will just fire. This will eliminate any over-travel.
Don't try to drill and tap because the parts are very hard and even if you do get it drilled you will never get a tap to cut threads.

Keep the gun properly lubricated and clean and practice with it as much as you can. I used to dry fire at the TV news folks until my daughter was born. After that I hung a target in the garage and dry fired at it. (it got me away from my ex who was an addict).
 
Not sure how much help this might be, but I have two GP-141s, and I replaced the stock springs in both. In one I used the Wolff Spring kit (10 lb. hammer spr./10 lb. trigger return), and in the other I used Wilson Combat's Ruger GP-100 replacement springs (10 lb. hammer/8 lb. trigger return). I replaced the first set about 12 years ago and the other about 4 years ago. Neither has had any issues with the springs in them right now.

I did find that using the Wolff springs, I would have an occasional light strike with the 10 lb. hammer spring and the 8 lb. trigger return spring; never figured out exactly why. I simply tried different spring combinations until I hit upon the combo that's in my SS GP-100 now. Since I originally installed the 10/10 combo, I have put several thousand rounds through it without a light strike, or any malfunction at all.

With the second GP, I started by putting the 12 lb. spring in with the 10 lb. trigger return to check how it felt. Then, I tried the 8 lb. trigger return spring, but still felt it was a bit heavy. And the reset felt a little mushy with the 8 lb. spring. In went the 10 lb. hammer spring and the 10 lb. trigger return spring. That felt and looked right, and has been problem-free since.

Also it is a good idea to smooth up the appropriate parts, either by a gunsmith or DIY. It does make a significant difference.

This is the video I used as a guideline; there's a lot of extraneous talking, but I believe "Yoda's" work is professional.

https://youtu.be/TuqticFg9q8
 
Use Federal primers with light hammers

I have a Performance Center S&W 627 and from the time it was new it would not reliably work with CCI primers. Everyone at my club that shoots competition with tuned revolvers swear by using Federal primers only. CCI primers are too hard for lighter hammers.
 
Ruger and everybody else uses springs stout enough to fire the hardest primers in the roughest gun they turn out.

"Spring engineering" may work if you have a smooth example, not if you have a rough one.

If you get a rough one, contact surfaces should be smoothed and camming angles corrected if you are to make a substantial reduction in springs. That is a true "action job." Lots of DIY text and video on how.

I snapped a gun the 2000 times recommended by the company service rep along with a good deal of shooting. My trigger finger may have been a bit stronger but the DA was not noticeably improved.

Federal primers are a way of life for competitive DA revolver shooting.
 
Guys ----

Excellent posts and info, too many to thank everyone individually, but each was read and each added something unique to the good ole knowledge base.

So two thing I glean (overall) from the thread (so far):

1. The Federal Primers were a good investment, and I should stick with Federal especially as I start shooting IDPA.

2. The Wolff Springs are not a miracle cure. Some fine polishing and lots of dry-firing may improve things tremendously without changing the stock springs.

Well, #1 is easy to accomplish, #2 make me a bit nervous as a "DIY" beyond dry firing. I've read that fit tolerances for a GP100 (or any DA) are tiny, and a few swipes too many (or even in the wrong direction) can result in an expensive red-faced trip to the gunsmith.

Here is one of the comments posted on a DIY YouTube Video. This guy went over the top with his criticism, but his warning does raise some eyebrows (Mine):

"I don't mean to offend you. I am a Ruger Factory Trained Armorer and what you did to the Double Action Sear has absolutely no major effect on the smoothness of the Action. The Double Action Sear is lifting and released on the toe. Stoning the Hammer is both reckless and ruins the Tolerances in the Frame as does Polishing the Hammer. There are much more superior techniques to Polishing which are not Tolerance destroying as what you demonstrate. Do you know how to fit the Pawl? Do you know how to fit the Hammer Dog, the Cylinder Latch? Do you know what causes "Hammer Jump", "Rolling Past Lock" and "Push off"? It just seems reckless to make an instruction video that is so wrong. There is no substitute for proper training by competent personnel."

Was posted on this video: https://www.youtube.com/watch?v=WqG5_2egsck&t=1077s
 
I snapped a gun the 2000 times recommended by the company service rep along with a good deal of shooting. My trigger finger may have been a bit stronger but the DA was not noticeably improved.
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I would be disappointed if my gun was noticeably worn in just 2000 pulls of the trigger. I would have the impression the parts were not very hard. That is why I believe in just taking the gun apart and polishing the proper areas. It can be done in 30 minutes.

And if your gun only fires reliably with Federal primers then I think your gun is defective. When it left Ruger it was set up to be as close to 100% reliable as the factory could make it. If you feel you needed a much lighter and smoother trigger then you should have bought a Colt or S&W. But you bought a Ruger. A gun that should give you about 4 life times worth or service with just a little care.

If you don't want to do or feel you are not able to do a polish job then send it to a gun smith and have the job done. It will cost a little but in the end will be worth the price for a smoother, reliable firearm.
 
12 lb mainspring and 10 lb return spring plus a good polishing and removing burrs on all the parts did wonders for me and is 100% reliable.
 
Spend the $15 on a decent stone and 30minutes disassembling and stoning the all friction parts and you will be rewarded. I'm no master, it was my first time on a revolver, and the difference is night and day. Watch a youtube video for assistance and take it slow and easy.
 
When you watch a gunsmith video you need to be aware that the smith using the stone automatically knows or should know the proper angle for stoning a critical surface. Don't be fooled into thinking that this is a simple operation. You could just as easily ruin a firearm as smooth it out.

There are stoning fixtures available to make it a foolproof procedure. I'm not in any way an expert. I'm just repeating things I have gathered over the years.
 
Arquebus wrote
Don't be fooled into thinking that this is a simple operation.
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When did I ever mention that this is a simple operation?? To the contrary I said just the opposite, that this is best left to the skilled hands of a smith for the exact reasons you just repeated.

Ratshooter wrote:
And if your gun only fires reliably with Federal primers then I think your gun is defective. If you feel you needed a much lighter and smoother trigger then you should have bought a Colt or S&W. But you bought a Ruger.
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I never said that either! I said it was experiencing FTF's after changing to a 10lb mainspring, that's all.

I purchased a Ruger because I wanted a Ruger, no apologies needed, the trigger pull was secondary to many other factors I considered. As I said in my original post the smooth trigger pull was just 'preferable'. If it can be smoothed out so be it, if not I'm fine with that too.
 
Did you install the hammer shims? If so did you clean up the scrap marks when you did that or could the marks be old?

After much tinkering and sanding my GP100 is as smooth as any of the dozen S&W's that I own. Don't let anyone tell you that the trigger can't be smoothed out. A couple of months a go I dry fired a Match Champion at a local shop and I was shocked. The trigger on my regular GP100 was significantly smoother and lighter. I ended up using the heaviest strength Wolff spring from the pack. It's a little lighter than stock. The lightest spring had a misfire every cylinder or so and the second lightest spring had a misfire every 50 or so rounds. But now it is 100% reliable.

If you aren't comfortable doing the action job I'd try and find a local gun smith who knows what they are doing and get a quote from them to see what kind of prices they would charge.
 
- CCI 500 SPP). Second trip to the range (yesterday), and it went down to 52 FTF out of 100 !! Only difference was the second batch was from a different box of CCI primers (500 SPP).
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Regardless of the manufacturer of revolver, when lightening up trigger pull by changing springs you WILL NEED TO switch to federal primers because of them being the softest on the market.
I am running the same spring package that you have installed and have no FTF's using federal primers. My S&W revolvers having 5.5-6 lb trigger pulls have had no FTF's
 
Lightening the springs makes it more difficult for the hammer to overcome internal friction, so, as mentioned, it's best done as part of a quality action job.

Once you get the action job, depending on how light (and smooth) your action is, you may or may not need Federal primers. But if you're going to compete, they're a good way to go anyway, since, in competition, your gear has to run 100% no-excuses reliably. Anything less will be costly, frustrating and unnecessary.

BTW, getting an action job is a good time to have the gunsmith chamfer the chamber mouths - a standard modification on runNgun revolvers. IIRC, the GP100MC is supposed to come with chamfered chambers, but IME, factory chamferings are very conservative and could definitely use some improvement. Do NOT chamfer (or a very light chamfer at most) the ejector star, though, as this can result in the ejector overrunning an empty case during a reload, which is very costly in a match.
 
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