Adventures in the Ruger GP100

[Bazoo]

Well, I've been wanting a GP100 for a few years and I finally got one. It was made in 1993. It appears to have been unaltered and not abused.

I first learned how to disassemble it. I made a Ruger popper out of a piece of short cleaning rod and bought a special bit from brownells to remove the extractor.

I carefully polished some of the internals, most notably the hammer strut and the trigger return spring channel. Nice and smooth, think I'll leave the factory springs. I changed the white outline rear sight and bought a black front sight to have the option over the red insert.

I've been working on some loads, with a borrowed RCBS 38-150-SWC. I have purchased my own and will continue both 38 and 357 load development. I also have a Lee 358-140-SWC that I'm working with.

I'll see about getting some pics in a few days.

Thanks for listening.

Bazoo

[megasupermagnum]

Don't be scared to try weaker trigger springs. Unless you are Jerry Miculek and can outrun a trigger, the 8# trigger return spring is a no brainer. And while the 9# hammer spring usually works, I've not heard of the 10# spring not working with all primers. I just finished my new GP100. It came with an average double action trigger, 4# single action with some creep. I followed Iowegian's guide, put in trigger shims, and used the 8# return and 9# hammer springs. So far 100% reliable. The best part is I have a buttery smooth 7 1/2 pound double action pull, and crisp 2 1/2 pound single action pull. My other GP100 has a 10# hammer spring, yet over time the trigger smoothed out such that the double action is similar, and the single action is a super crisp 2 1/4 pounds. The GP100's can have phenominal triggers, as good or better as any S&W I've ever witnessed.

You would be shorting yourself if you didn't try the 175gr Keith bullet and 10 grains of Bluedot. I've not found a 357 magnum this didn't shoot great in.

[Bazoo]

Thanks for the reply MSM. I'm reluctant to change the springs because I like a little heavier single action pull than most. 4 pounds but crisp is right where I want to be. I don't have a pull gauge but I'm pretty close, knowing that my 1911 is 5 pounds. That said I may change the trigger return spring to 10 pounds to see how I like it.

I plan to shim the trigger at some point but not the hammer, for ease of disassembly. I'm not a member over on Ruger forums but I have seen a lot of Iowegans posts.

Are you talking about the Lyman 358429? I don't have one but currently. Are they too long for the GP cylinder in magnum brass (seated to the crimp groove) in your experience? I just got some bluedot to experiment with, so I'll be trying it in both 357 and 44 special / magnum.

[megasupermagnum]

Yes, the 358429 or clones. I use the NOE 360-176-SWC, as I like to play with hollow points. If I only wanted solids, I would go for the Arsenal molds version. They fit crimped in the crimp groove no problem. I load to 1.645" OAL The GP100 could handle up to about 1.660" or so, but I like to leave a little wiggle room. As far as I know, the only gun they wont fit in is the S&W 27, although I'm sure there are a couple other short ones.

[megasupermagnum]

What really helps is the hammer dog shims. The hammer dog usually has a ton of play. It cleaned up a notchy DA feel in mine, which was likely the transition from hammer dog to DA sear. Both my GP100's had tight frame to hammer fit, and I doubt shimming there did any real good. I seem to remember my shims on both being .002", one on each side. It makes me happy that my hammer doesn't rub is about it.

One nice thing about leaving the heavier springs, they almost seem to cover up any grittiness.

[Bazoo]

Preciate the advice. I might give the lighter springs a try sometime but I am fairly content with the trigger pulls.

I think I'd like to chamfer the charge holes. Got to learn about it though as I'm not familiar with what's required or any disadvantages.

I am still looking for a holster to get me by until I can make one to suit me.

[dannyd]

Have fun with it I have 5 started in 1989.

[tward]

Great gun! I’ve had one since 1993 and have not found a load that won’t work well. I did change the springs and put fiber optic sight on it, way better for old eyes. I’ve loaded everything from round balls to 200gr. And they all shot well. Round balls are fun and quiet, think civil war 36 cal. Tim

[contender1]

Kudos on getting a fine handgun. I'm a LONG time Ruger collector & shooter. I was totally happy with my Security Series DA Rugers & didn't have a "need" for a GP-100.
Then,, I handled a Match Champion. I had to have one. Then a regular GP became available for a very fair price. It moved in. Soon after,, another GP with a longer barrel did the same thing. Next,, along came the MC in 10mm. Oops,, now I own several GP's!

Most guns benefit from a good, careful action cleaning,, and sometimes spring changes. A smooth action is what most prefer,, and a clean crisp trigger is what works best. And,, it can actually be heavier than you think,, if the action is done right. (I have one gun,, that most swear it has a 1-2 lb pull,, but it will measure 3.5 lbs all day long.) Shims do assist in reducing drag & helping keep things smooth.
Too light of hammer springs can result in misfires.
Iowegan has some excellent info,, and on the original Ruger Forum,,, there are also some very knowledgeable folks. The original Ruger Forum,, (the .com one) has internet server issues,, and you can't join,, but a member over there also frequents here, is a top notch Ruger DA gentleman. RoninPa is his handle over there. I can't recall if it's the same here.
But if you need anything I can put you in touch with him. He's a gunsmith, and a FFL.

You mentioned chamfering the charge holes,, and I can attest to the FACT that our own DougGuy can & will do this. I had him do a S&W 646 for me for competition. You can bet it'll be right,,, AND his prices are very fair.

[Bazoo]

I appreciate the replies. I had thought about Doug. I want to learn it myself though if I'm able. The wife's 686 could use it too.

I'm still young and poor. I have less than 10 firearms, but the ones I have I enjoy and master. Shooting the wife's 686 is okay, but I'm glad to have my own. My GP grips help reduce recoil a lot compared to the wife's open backstrap and wood grips.

[dannyd]

I appreciate the replies. I had thought about Doug. I want to learn it myself though if I'm able. The wife's 686 could use it too.

I'm still young and poor. I have less than 10 firearms, but the ones I have I enjoy and master. Shooting the wife's 686 is okay, but I'm glad to have my own. My GP grips help reduce recoil a lot compared to the wife's open backstrap and wood grips.

Load some light loads and enjoy the gp.

[Petrol & Powder]

I really like the GP-100. Strong, accurate, strong, reliable, did I mention they are strong

They do respond very well to some judicious polishing and shims. Like the OP, I avoid shimming the hammer to make disassembly/re-assembly easier.

To maintain a crisp and rapid trigger reset, I sometimes leave the factory trigger spring in place. A slightly lighter hammer spring is a useful modification, particularly after polishing/shimming the action. Ruger uses some seriously heavy springs and you can safely drop the weight of the hammer spring by a few pounds without affecting reliability. There are some drawbacks to reducing the hammer spring weight by too much; at some point reliability will suffer and lock time will increase as the hammer spring gets lighter.
The GP-100 can be a very accurate gun. The GP-100/S&W L-frame debate has been going on since the introduction of the GP-100. I think the GP-100 is every bit the equal of the S&W L-frame and the GP may be a bit stronger due to its solid frame (no side plate) and locking crane. However, that's sort of like saying a 100lb anvil is stronger than a 98lb anvil.

Ruger introduced the GP-100 a few years after the S&W L-frames but I think they really hit a home run with that design.
S&W discontinued the fixed sighted L-frames (581 & 681) but the adjustable sighted 686 lives on.
You can still get a new GP-100 with fixed sights in 3" barrels and 4" barrels (in the Match Champion line).

Congratulations on obtaining a fantastic DA revolver.

[onelight]

Good job Bazoo !
I have had a Gp100 a few months now and it is very easy to shoot well.
I hope you enjoy it.

[Bazoo]

Thanks all. I have already made both specials and magnums to test. So far I'm getting 2.5"-3" groups rested at 25 yards, but I'm working on cutting that in half. Not sure if it's me just needing to familiarize myself more with the gun or something with my loads.

[Xringshooter]

Thanks all. I have already made both specials and magnums to test. So far I'm getting 2.5"-3" groups rested at 25 yards, but I'm working on cutting that in half. Not sure if it's me just needing to familiarize myself more with the gun or something with my loads.

I will tell you with some confidence, the more you shoot the GP the better it will get and so will you. Loads do have a lot to do with it but being completely familiar with your firearm really helps.

Member "Contender1" (post #9) referenced me from the RugerForum.com (thank you Ty). I use a different name here, picked up when I was shooting PPC many moons ago. I actually built a PPC competition revolver from a GP100 in 1992 and got heckled a lot from long time PPC shooters - until I let them shoot my revolver. Then their tune changed. Most PPC guns at that time were mainly made from Model 10 S&W's, no one (but me I guess) really considered using something else. I replaced the 6" barrel with a bull barrel and adjustable (4 positions) sight rib. I went with a (at that time) Bullseye brand 6lb trigger return spring and a 9lb hammer spring for the lightest trigger pull and reliable ignition. The 9lb hammer would not reliably ignite factory ammo but worked perfectly with the reloads we shot (.38 special cases, 148gr HBWC, 2.5grs Red Dot, Federal #100 primers (the softest primer cup primers). Polished the internals like you said you did as well as the sear, hammer notch, sides of the hammer and the insides of the frame where the hammer goes to remove any/all burrs and to polish it. Finished with a Hogue finger groove Monogrip. You wouldn't know it was a Ruger unless you looked at it up close That gun would hold it's own with any PPC gun on the line. Never used shims (didn't hear about them back then) but probably wouldn't have used them anyway as good as my revolver shot.

I wish I still had that gun. But I was in the USAF at the time and was selected to join a special maintenance team to go to Egypt to help the EAF open a new F-16 base. Sold it to a good friend and PPC shooter and lost track of it over time.

I now have a pretty fair collection of the Six series Rugers (Security, Police Service and Speed) and GP100's. I'm kind of endeared by the Ruger double action revolvers (all of them to include the SP101's and LCR's) and get ribbed by the Ruger SA collectors (all in fun). I do specialize in the repair and refurbishment of Six series and the GP100's in my small (me) gunsmithing/Cerakote business.

Bazoo, in my estimation, you will never be disappointed in purchasing Ruger double action revolvers, old or new.

[onelight]

Thanks all. I have already made both specials and magnums to test. So far I'm getting 2.5"-3" groups rested at 25 yards, but I'm working on cutting that in half. Not sure if it's me just needing to familiarize myself more with the gun or something with my loads.

There are guys here that can shoot better , but for me 21/2 to 3" at 25 yards with an iron sighted revolver is a good day.

[Bazoo]

Thanks xring for your post. I did some other polishing also, but in stages. The trigger opening, the sides of the hand, the hammer and trigger area for the double action pull and for cocking the single action. I can't think of what that's called right now. I didn't get wild on it, and I didn't smooth all the machine marks off. I used 600 grit sticky back paper adhered to a steel ruler and then some green polishing compound on a backer. I studied it well to make sure I understood how it worked before starting.

I removed some sharp edges and smoothed some where the trigger guard latch rubs. That made disassembly much easier.

[Shawlerbrook]

I have a used GP100 in 357 I bought in 1992. Accurate and like said above, STRONG !

[Xringshooter]

Where the trigger guard latch goes into the frame is a much missed area when people are "cleaning up" the GP100 as well as the hole that the latch and trigger return spring go into. Many don't think about those areas but it can help in the smooth functioning of the gun overall. The biggest thing when polishing around the sear and the notch on the hammer is to keep the angles the same and just polish the surfaces. You don't want to change any angles, that can lead to bad things happening, but I think you already know that.

The part on the trigger just below the SA sear is called the secondary DA pickup and on the hammer the part above the SA notch doesn't really have a name. Also, smoothing up the part above the sear (called the primary DA pickup surface) will help make the trigger pull feel smoother as that part is what first contacts the hammer dog when shooting in the DA mode.

[DougGuy]

You can ream the throats yourself, the expense comes in the piloted reamer vs. the solid nose reamer. The solid nose diameter is so much smaller than the throats, it might as well not even have a nose on it, you are pretty much going in blind without anything to keep the flutes centered.

The next thing is cleaning up the tool marks left by the reamer which will be considerable. If you are targeting .3585" which is the most requested size and which is correct for .358" boolits, you have to hope the reamer cuts small enough to leave you enough meat to finish at .3585" without leaving so much that it becomes a secondary chore to take throats out where a .358" boolit slides through with finger pressure, and then you have to be really diligent in keeping throat diameters consistent enough that it minimizes any pressure variations which will open groups measurably.

Two cylinders honed on precision equipment to a factory like 800 grit finish are considerably less than the cost of the piloted reamer, two cylinders honed and chamfered are only a tad bit more than the piloted reamer, and you still have all the cleanup to do after reaming.

I started years ago with reamers and a split aluminum rod then moved fairly quickly to the ACME laps and valve grinding compound to clean up after reaming, none of the equipment I started with or the techniques and materials I used even came close to the results and the accuracy of the Sunnen hone..