M*CARBO Brotherhood

Ruger GP-100 Gunsmithing

Hello MCARBO Readers:

I have been wanting for a while, to post an article showing the gunsmithing work that I have done to my Ruger GP-100 for a while now. However, it has taken me all this time to finish the work that I have done. I used to own a 6 inch GP-100 when I was younger. I loved that GP-100. It was rugged, durable, reliable, accurate, and a fun gun just for target shooting. As hobbyists, guns come and go. I regret letting go of that GP-100. It has been many years now, and I still miss that revolver. There is something about shooting a well tuned DA revolver trigger, and mastering that trigger pull, that I love. I have owned many different auto pistols, Glocks, Smiths, Taurus, but I really wanted to get another GP-100. So back in April of 2019, I decided to purchase a 3" fixed sighted model for home defense and target shooting. I tend to like fixed trench sights because they are more rugged and durable than adjustable rear sights. Ruger trench sights have a better sight picture than does Smith and Wesson revolver trench sights. I wanted something with a shorter barrel length for conceal-ability, but not quite as short as a snubby, so I can get at least some decent velocity and sight radius. By going with a 3" GP-100, you get 1 extra round than a snubby, more weight to control recoil, and the better velocity and energy of the .357 Magnum over the .38 Special rounds. I use Barnes 125 grain Tac-Xp at around 1,200 fps, which is about like a +P 9mm in recoil and energy, but this round expands to over .70" and penetrates like 15 inches in ballistical gelatin! I
hand load all my own ammo. I’m also a big fan of the 120 grain Xtreme Defense rounds from Lehigh Defense.

When I first purchased my revolver back in April of 2019, it was a diamond in the rough-- REAL ROUGH! There were heavy milling and machine marks everywhere. Some of the edges were too sharp. The trigger was grainy and was over 14 lbs. There was even a burr in the rear sight notch. The cylinder release latch was sticking, and the rubber grips that came with the gun just didn’t fit my hand very well. The fit and finish of the Ruger revolvers has indeed declined over the years. But despite all of this, the Rugers are still really well made, durable, reliable, accurate firearms, well worth every penny. I indeed decided that it was well worth my time, money and effort, to turn this diamond in the rough into a family heirloom.

I have previously done minor gunsmithing work on bolt action rifles, trigger jobs, mounting scopes, AR upgrades, Glock upgrades, etc. After watching the MCARBO instructional video for the Ruger SP-101/GP-100 trigger job, shim and muzzle crowning, I felt that such an undertaking was within my capabilities. I disassembled the revolver into it’s components. I decided that the first course of action was to thoroughly clean the revolver. I discovered that some of the internals already had small spots of rust on them! The pistol had been manufactured in March of 2019. Again I had purchased it in April of 2019! So in the course of one month, this stainless steel revolver somehow developed rust??!!

I quickly treated the areas with WD40 and scrubbed with a green nylon scrubbing sponge until the rust went away. I next crowned the muzzle using the lapping compound and special brass drill bit that came with the kit. I did this with light pressure until the crown was smooth, then followed up with the polishing compound, then swabbed the bore clean. Using a Dremel tool, I VERY carefully used the special felt bits and polishing compound to polish the areas as described in the video to smooth out the components and trigger action. Two things that I want to make the readers aware of, is to be very cautious not to allow the felt bit to accidentally slip and to nick the finish of the gun (which is very easy to do). The other is to be very careful NOT to take off too much material when polishing on the cylinder latch. If you do, the cylinder will have way too much side to side wiggle. I found that to be the case, and I had to order another cylinder latch. The part cost $3.69 plus shipping.

The trigger springs as they come from Ruger factory for the GP-100, consists of one OEM 14 lbs. hammer spring, and one OEM 12 lbs. trigger return spring. The MCARBO kit included four .001" trigger shims, four .005" hammer shims, PTFE lubricating grease, one 9.5 lbs. hammer spring, and one 7.5 lbs. trigger return spring. I also ordered a polymer gunsmithing block from MCARBO, the feed ramp polishing kit, which includes felt bits and a tin of polishing compound, extra felt bits, and the muzzle crown/lapping kit. I ended up having to order four more .001" trigger shims, as the the four that came with the kit weren’t enough to do the job. Two .005" hammer shims were sufficient for my gun. I also ordered the Wolff spring kit as well, just so I can tune in the trigger weight to exactly where I wanted it to be. The Wolff kit came with 9, 10, and 12 lbs. hammer springs, and an 8 and 10 lbs. trigger return spring. I wanted reliable primer ignition, a light and smooth trigger action, with reasonable fast trigger return. For my gun, I ended up using The MCARBO 9.5 lbs. hammer spring, and the Wolff 8 lbs. trigger return spring. The 10 lbs. hammer was somewhat too heavy, while the 9.0 I feared would produce light primer strikes. The 7.5 lbs. return was a little sluggish on the return, while the 10.0 Wolff trigger return spring was too heavy. What I ended up with was perfect for me. I want to say that I never touched the edge of the sear and trigger surfaces, where the parts meet, because I didn’t want to take any chance that the sear would disengage on accident. I only polished the cycling surfaces as described in the video. After polishing and changing out the springs, I used my RCBS trigger pull gauge to measure the weight
of the trigger pulls. The average was 7.5 lbs. double action, and 3.0 lbs. single action!! It is SO smooth! I couldn’t believe what I had accomplished!

I then spent over the course of weeks, approximately 30 hours polishing the external surfaces of the revolver, until it was as good of a mirror that I could get it! The original matte finish had DEEP milling marks that were almost impossible to get out. And although I did not get them out completely, I did the best I could, and I am very satisfied with how the pistol turned out! I wanted to put a tritium front sight on the revolver, however, NO ONE makes a tritium front sight specifically for the Ruger GP-100!!?? How can this be?! The Ruger GP-100 is an iconic revolver that has been around since 1989! And no one makes a tritium front sight for it?? I was incredulous to say the least. I called XS and talked with one of their gunsmiths. He told me that “their” XS front sights for the Smith and Wesson 586/686 would work on the GP-100, but might need fitting, drilling and installation by a local gunsmith. Their front sight was about $80.00. I saw a Meprolight S&W 586 tritium front sight for about $30 on Amazon, so I bought it. Yeah, I wasn’t that lucky. It won’t fit.
The front of the sight doesn’t line up, and the under lug is too big and would need to be filed down. So I had a choice, I could spend money and try to see IF the XS standard dot front sight would work on the GP-100, or I could try to use GLOW-ON, glow in the dark gun paint. I decided to give GLOW-ON a try. I applied the GLOW-ON with a tooth pick, let it dry, and then put clear nail polish as a protective enamel over top. It worked great! The only draw back to the glow in the dark paint, is that you have to activate it with a light source (LED works the best), for 10 seconds, prior to use. But on the upside, once activated, it stays glowing for hours. As a night stand gun, one could activate the paint prior to turning in for the night. Or as a carry gun, one can activate the paint prior to holstering. Not quite tritium, but it works.

My attention was finally turned to the grips. If the gun doesn’t fit comfortably in the hand, and if one can’t shoot well with it, then all is for nothing. Having the absolute best set of grips FOR YOU is absolutely critically important. Every person has different hands. What may work very well for one person, might be too big or too small for another. And it is one of those unique phenomenons with revolvers, that owners most of the time, have to go through buying quite a number of different grips, until just the perfect one is acquired for both the gun and the user. This was the case for me. The original grips that came with my GP-100 was the Hogue Rubber Black Monogrips, pebble textured with finger grooves. These were quality grips, however the finger grooves were too large for my hands, and for a revolver with an MSRP of $799.00, I wanted exotic hardwood quality to compliment the luster that I was trying to achieve. I then ordered for around $100.00, Badger Custom Sport Grip, in dymalux laminate rosewood. These grips would support ALL fingers, which was important to me for recoil control. When the grips came, they were beautiful, very well made and they fit the revolver perfectly! However, sadly, the grips did not fit my hand, and the grip angle for me wasn’t natural as I thought that it might be. The area around the pinky finger was way too small. And the area around the ring and middle finger was way too thick. So I ultimately decided that I was going to buy Hogue wood grips. But before shelling out $144.00, I wanted to make sure that the grips would fit my hand. As a test I ordered the Hogue rubber monogrips with no finger grooves, just to see how these would feel first. I also simultaneously ordered the original Ruger factory rubber grips with the wood panels, that they first came out with in 1989, just because I wanted to have an OEM grip for the gun, and also I wanted to see how the OEM grips felt in comparison to the other grips. For me, hands down, the Hogue rubber monogrips with no finger grooves felt the best in my hand. The Ruger OEM grips were almost similar in feel, but was a little more blocky around the middle, and a little too narrow up top. After playing with the Hogue no finger, rubber Monogrips for about a month, I decided to go ahead and make the purchase of the the Hogue wood grips. I chose the dark rich solid Rosewood (non-laminated), with dragon scale texturing. This gave an old world kind of luster to the pistol that is absolutely gorgeous. The Hogue grips are a solid one piece construction, not two side panels. They have a track inside the grips, with a stirrup and pivot pin, that attaches securely by a screw in the bottom of the handle. The Hogue wood grips secured to the GP-100 with a tight fit with no wobble. And most importantly, the grip angle was perfect, and it fit my hand perfectly. One thing I noticed about this grip and gun combination, is that along with fitting my hand perfectly, the rigidity of the wood somehow to me perceived better control of trigger manipulation.

All of this together was perfect! It is now a gorgeous family heirloom that I am very proud of. Thank you MCARBO!

Sincerely,

S. Lacey!
Akron, Ohio

P.S.: I would liked to have posted many more pictures, but I’m a “new user”.

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Ive had several Rugers over the years , rifle and pistols. some have come and gone, but the ones that have endured are my Ruger #1 rifles. pistol wise, my DIL “borrowed” My 357 Black hawk in a XR3 RED frame, so after i saw how it fit her hand, I gifted it to her, holster and all. mY next will be a brace of the “Old Army” black powder .44s. the stainless models. I plan on doing them, the same as you have done the GP.
nice work by the way.:+1::+1::+1::+1::+1:

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@slacey welcome to the forum shannon

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@slacey
Welcome to the brotherhood :v:

My beginning here is very similar to yours.
Attached is the link where, when and why I joined.

I saw a video on YouTube of our “Fearless Leader” Chris Nelson doing a polishing job on a Ruger SP 101. Watched it several times. In fact, I looked at other videos too. Choose to go with MaCarbo because of how Chris presented himself, and his Enthusiasm was contagious. Ordered the parts, join the Brotherhood and went to work on it.
Turned out just way cool✌️
I too had a GP 100 in 6” that got away from me many moons ago. Now I have one in 4.2” that will stay with me forever.

Yours is Way Cool :v::v::v::v:
Good job.

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I recently received my GP101 trigger kit and muzzle honing bit. I’m geared up to perform the job and this thread gives me some extra enthusiasm. I’ll post how it goes and what the results are. Stay tuned!

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