GP100 - Hammer/Trigger Spring Questions

H

HisDudeness

New member
I did some research regarding spring changes on my GP100 and I would like to pick your brains a bit. From what I've read the stock springs are 14 lb hammer and 12 lb trigger. From what I gather the hammer spring is responsible for the primer strike pressure itself and the trigger reset spring, hence the name, is responsible for resetting the trigger after firing. I've also read that changing the hammer spring can improve DA trigger pull while changing the trigger spring can improve SA trigger pull. A couple points before I get to my questions:

-This IS my home defense gun of choice.
-We ONLY fire this revolver DA so I'm not too concerned with SA trigger performance.
-I use this gun just about weekly at the range and I would like to improve the DA trigger for my wife. She has improved her accuracy tremendously since I turned her on to shooting but I figured why not try for more. I started her with 22LR until she was no longer intimidated by the GP100.

Now being that this is a revolver, should I keep the trigger spring stiff while reducing the hammer spring weight? I figured a failure to reset the trigger would be disastrous while a failure to fire might be corrected by simply pulling the trigger a second (or third) time. I guess I'm looking for a compromise between a lighter DA trigger and dependable reliability. I realize that everything is a compromise but please let me know if I am off base here. I've seen recommendations of 12 lb hammer and 10 lb trigger or 10 lb hammer and 8 lb trigger. I use high quality factory .38 ammunition for home defense, would staying away from CCI primers aid in reliability with a reduced spring weight? If you have personal experience with changing springs in your GP100 how have your results been?

Thank you in advance.
 
Strange you mention CCI primers and reliability...

I had two rounds out of 6 that I made up for testing fail to fire yesterday in my 686...Repeated strikes in the 686 did nothing, yet they fired in my Blackhawk first strike...

CCI 550 primers...I have fired maybe 300 out of the brick without a hitch in my Rugers in the last month...I then fired another 20 rounds of old Bullseye remanufactured .357 mag out of the 686, and it worked flawlessly...

Only conclusion I can come to is that the primers were 'hard'...

Sorry for the OT, but you got me thinking out loud...
 
If it's a defensive gun, I'd not mess with the spring, but I understand the feelings about your wife being able to shoot it. If I had to pick one, I'd go with the hammer spring/main spring. Stick with whatever ammo goes boom every time. If you're out practicing, use whatever you want. When it comes time for the real thing, you'll want the most reliable ignition you can get.
 
Changing the hammer spring to a lighter one does not have much noticeable effect on SA trigger pull. It will have an effect on how fast the hammer takes to fall (lock time). The longer the lock time the more chance you have of moving the gun a little after pulling the trigger. That will make accurate SA shooting at distance harder. Changing the trigger return spring will have a noticeable effect on DA and to a lesser degree on SA. If most of your shooting is going to be DA I would leave the hammer spring at factory power and go lighter (in steps) on the trigger return. If the trigger return is too light the trigger will return forward sluggishly which will handicap you in fast DA shooting because your finger has to "wait" for the trigger to reset (not goog on a CCW gun). If you like to do a lot of long range SA work then going to a slightly heavier hammer spring will decrease the lock time and help on the distance shots. Most of the long range guys I know who shoot SA revolvers all use heavier than factory hammer springs. If you want to set the gun up with the lightest possible trigger then you should use nothing but Federal primers or ammo. They require the least amount of impact to ignite. CCI/Speer are the hardest to ignite. All of my guns (except the CCW ones) will bang a Federal primer every single time but any other brand may require a second strike. For a defensive CCW gun forget about very light triggers. In a SHTF situation you will not notice the trigger pull weight. Light triggers are for competition and range guns only. A carry gun should be smooth and crisp but doesn't need to be "light". Most of the trigger work done on revolvers involves removing burrs and reducing friction between the moving parts and perfecting the hammer/sear angles (they should be close to perfect right out of box). Once that is done the trigger pull will be very good even with the factory springs installed. Ruger revolvers have always been notorius for very rough finish on parts and frames and are full of burrs that need to be stoned away. They are very solid reliable guns but they save you a lot of money by not polishing everything out like say S&W or Colt.
 
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If most of you're shooting is going to be DA I would leave the hammer spring at factory power and go lighter (in steps) on the trigger return.
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So apparently I had that completely backwards and it's the trigger return spring that should improve DA shooting. Thank you drail.
 
Yes, going lighter on the trigger return will not reduce reliability at all. You just have to decide how important fast trigger reset is to you. Most spring kits will give you 3 choices on trigger springs. The middle one is almost always the best for DA work. But like I said getting all of the burrs out will help the DA pull tremendously. The hole that the trigger spring rides in on a Ruger is normally full of burrs. Clean that hole up and you'll get a better DA pull. With spring slightly lighter than stock it will be much easier to cycle in DA. You can use a wood dowel with sandpaper wrapped around it and get most of the defects out. Be sure to flush all of the grit and chips out before reassembly. If you change the hammer spring for a lighter one make sure to thoroughly test it with whatever load you will use for self defense work until you are confident it will go bang every time. This is crucial. Polishing the edges and rounding off the corners of the strut the hammer spring rider on will make DA smoother. My wife has a Ruger GP that she had setup for competition use and it is very nice for a Ruger in DA but it cannot compare to a S&W that has been worked over by a good revolversmith. But she loves that GP.
 
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I own a GP100 and I changed the springs to the Wolf ten pound trigger spring and the eight pound hammer spring. The result was that I had an average of two misfires per one hundred rounds. 2%
I then went back up to the ten pound hammer spring and I have had zero misfires through the last 250 rounds of mixed brands of ammo.

DA is still very manageable
 
-This IS my home defense gun of choice.
-We ONLY fire this revolver DA so I'm not too concerned with SA trigger performance.
Click to expand...

In this case, you can have your cake and eat it too if you convert to DAO by bobbing the hammer. The lighter the hammer, the better. With less mass, a lighter hammer takes less oompf to get it moving, so you can reduce spring tension while retaining reliability. My S&W 686, for instance, has a radically bobbed hammer, and a 7.5 lb DA trigger pull weight, and yet it's fired everything I've fed it. And with less hammer mass comes less jarring of the muzzle upon hammer strike, so you gain some bonus accuracy to boot. Here's a demo of this affect:

http://www.youtube.com/watch?v=lmy5mkjpUNI&feature=channel&list=UL
 
Here`s my recommendation & my preference .

While ya have it all apart round the hammer spring strut edges so the spring will smoothly flex ,pay attention to how it`s oriented , install the 12# hammer spring for 100% reliability (SD/HD)

As ya have the trigger group apart take a 13/64 drill bit & fine lappin compond & polish the well that the trigger spring & plungers ride in ,upon cleanin throughly this is 1 place I use a synthetic grease for lube, install the 10# trigger spring, remember the reset speed relies on this spring to pull the transfer bar out of the way if the hammer drops without the trigger being pulled.

I strongly recommend you visit triggershimms.com & get the kit for the GP ,it`ll center the hammer & stop frame drag (kinetic power robbing) & with shimming the trigger it`ll make the pulls both SA/DA alot more consistent.

Polish surfaces ,DO NOT remove metal or reshape parts !!
DO NOT hone or polish trigger/hammer sears with out correct tools (Ruger does not sell these parts & used 1s untouched are far & few)

On the shimms when ya measure the gap (feeler gage) subtract .003" then split it , do this before ordering as Lance makes different thicknesses.

Go slow , don`t pull the trigger when the group is out of the frame as parts will move & springs/plungers (2 of em) will eject . I suggest a gallon ziploc bag for disassembly until ya learn the dos&don`ts of the group.

Go slow , pay attention to the plungers (2 different sizes) It`s not a hard system to work on there`s just certain steps for dis/re assembly.

102_0702.jpg
 
This IS my home defense gun of choice.
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My opinion leave the revolver alone "IF" it will be your home defense gun. Are you willing to risk the gun not firing because of lightened up springs for the sake of trigger pull reduction?
I have tried the spring kit from Wolf and with my reloads have had mis-fires with the lighter hammer springs installed and have gone to the #12 spring instead of the #14 factory spring. With the #8 spring it was mis-fire nightmare, 3 of 6 would not fire.
Wolfs web sight states that for the S&W springs they "DO NOT" recommend the lighter spring for a SD weapon.
Still your choice in the end, choose wisely.

I just read GP100man's post and that proves my issues with mis-fires
 
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Thank you for the responses.

GP100man, I had a couple of questions:

While ya have it all apart round the hammer spring strut edges so the spring will smoothly flex
Click to expand...

I'm guessing this is an exception to your polishing only and not reshaping the metal comment? I would do this using a fine grit sandpaper correct? Do you use polishing compound along with the sandpaper to achieve this?

As ya have the trigger group apart take a 13/64 drill bit & fine lappin compond & polish the well that the trigger spring & plungers ride in
Click to expand...

I'm not sure what a lappin compound is, would a product like Mother's Mag metal polish suffice? I can attest to the quality of this product after using it to beautify a very ugly S&W 5906.

I believe I will take your advice and clean up the strut and the strut well. I don't see how I could negatively affect function or cause any damage by doing this. I will also add the shims you spoke of. I will NOT touch the hammer sear or the like as I've been warned a few times now that these parts are very unforgiving. The possible improvement is not worth the risk to me.

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As to the comments about leaving the revolver alone since it will be used as a home defense device, I can understand your thinking. But as I said before I believe a compromise can be had here. I've seen the 12 lb. and 10 lb. setup floated a few times now on this site and others. It seems that this is the most reliable setup using lightened springs. Others have noted an improvement over the stock springs with complete reliability using this setup. Not the lightest trigger possible but definitely reliable; a compromise. I will also be confirming reliability as we shoot this gun almost weekly.

MrBorland:

Bobbing the hammer is something I never even considered. Unfortunately I would not feel comfortable doing this myself and I want to confine this project to the garage. I would also like to keep the aesthetics the way they are. Think of it like one of those expensive high performance spoilers you see kids so often putting on their Hondas. I will never use the hammer spur as it was intended but I do like the way it looks on this particular gun. Now if I ever decide to purchase an SP101 like I've been contemplating I will definitely buy the model with the bobbed hammer.

I also watched your video showing your prowess with a speed loader. Very impressive! :eek: That is probably faster than I could reload just about any firearm, including a magazine fed pistol.
 
To radius the hammer strut edges will require a great deal more than polishing. I usually start with a mill file and round them over and then finish with 220, 400 and 600 grit sandpaper. Brownells actually sells a replacement hammer strut for a Ruger that is completely round. That is the way the part should have been built at the factory but they opted for stamping them out of flat stock to save money. Everything the hammer springs touches should be round and very smooth. It doesn't have to be perfectly round but it does need to be completely without square corners on it. A little dab of grease on the strut helps also. You can certainly make compromises with spring rates but on a "business gun" anything that is done that can possibly reduce reliability needs to be thought about real hard, especially if you want it to run with whatever brand of ammo you might acquire. I have seen many cases where a revolver was worked over and eventually meet a primer it just couldn't quite ignite even after being 100% reliable with other brands. If you think of trigger jobs as light, medium and heavy pull weights, what you want is somewhere between medium and heavy. Unless you are physically handicapped you can learn to pull a DA trigger smoothly even if it takes a little muscle work to do it. Smooth compression and release and reset is far more important than a LB. or two of pull weight. I have had been able to tune S&W trigers to ridiculously light weights in DA but only with Federal primers seated full depth. But I discovered when I started tuning carry revolvers that light DA pull is just not necessary or wise on a carry gun.
 
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I don't have a Brownells in front of me now but be sure to check the fine print to be sure it os for a GP and not a single action Ruger. The SA one won't fit. ALWAYS read that fine print.
 
Yes you can use more aggresive means on the strut as it1s fitting is`nt as critical as the other parts.As long as the finished product is smooth.

Turn the bit backwards in the drill ,using the shank, & mothers will be slower but a hi polished surface for sure .

I have`nt look in Brownells in a while ,but I know they carry a round strut fo SAs.
 
Mr. Borland, that video is quite impressive. I'm sure your revolver is slicker 'n snot on a doorknob and that helps, but your skill with it is the bigger part of what you are doing with that nickel. I am impressed -- but not surprised, I've seen your targets. :)

That is a radically bobbed hammer. Do you use CCI primers? I use them exclusively and I'd be afraid of misfires. Most folks who handload revolver ammo for target/competition are married to Federal for exactly that reason.
 
FWIW, I agree with not changing things in a defense gun. I know the temptation to advise tuning this and changing that and grinding something else. BUT, will the folks who give all that advice agree to be responsible if you take it and the gun doesn't work when you need it? (Do I hear silence?)

I have worked over a fair number of revolvers, including one I carried almost daily as a deputy sheriff. But for someone with less experience to go chopping and channeling and changing springs willy-nilly, is not, IMHO, a good idea. There are few adults who can't handle a reasonable weight double action; more practice (dry fire) time might be a better bet than altering a gun you might need very badly.

Jim
 
Thanks, Sevens.

The hammer is more radically bobbed than you'd normally see, as the entire back of the hammer was lobbed off, which opens the action to all types detritus, so this type of bobbing is typically reserved for match-only guns.

As it is a match gun, I do use Federal primers, but it's shot anything I've fed it, including handloads with CCI primers, though I'll admit to handseating CCI primers for a little extra insurance. Nonetheless, I still go Federal-only for actual match ammo.
 
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