Gemini Customs Ruger GP100

Ultimate 7-Shot Big-Boomer Belly Gun!

I was chatting with Marc Morganti, the founder, owner, solo gunsmith and simply put — the really smart machinist guru at Gemini Customs. Trust me on this last bit, by the way. I asked him, simply, “Why this gun?”

The Why Factor

“The Ruger GP100 is a lot like a small block Chevrolet engine to me,” Marc explained. “The same basic foundation can be configured into sidearms of different calibers and capacities. It’s amazingly versatile.

“But it takes someone with vision to see what can be done with one.

“I started building this particular 7-shot .357 magnum configuration about four years ago using the Ruger GP100, their model 01780 to be precise, in 10mm Auto. I also use the Ruger model 01774, a 7-shot .357 Magnum,” Marc continued.

“Some people refer to this as building a ‘Frankengun,’ which makes a certain amount of sense. There is some parts swapping, lots of fitting and tuning, donor guns and recipients and of course my ‘Ultimate barrel’ I machine here in the shop. So, it does seem to be a compilation of bits and pieces to the uninitiated.”

Ah, but I can tell you from firsthand experience this is no parts-box AR made in a garage from gun show scores and a beater frame. There’s an obviously experienced artist’s eye at work with a Gemini build. The sum of the parts merge seamlessly into a final whole. No shortcuts, “almosts” or compromises here.

“In fact my first Frankenguns were .44 special conversions. You even wrote one up in Handgunner a few years ago, and I appreciate that,” said Marc. “Back when Ruger revolvers were not so scarce, I built about a dozen or so of these using the 7-shot .357 Magnums with the Ruger GP100 ‘Wiley Clapp’ frames sporting the Novak Lo Mount rear sight. They were and still are very popular and I always accept customer guns to build on, especially in these trying times getting new guns,” laughed Marc.

Gemini Customs Gear List: Ammo: Federal 158-grain HydraShok,
Belt: Galco Casual, Knife: Finch Reciprocity

Unique Ideas

This particular build is a bit unique for Marc’s shop. Since he left building custom 1911 some years ago, Marc has concentrated on revolver work, always pushing the envelope with design and function ideas.

He likes a good idea and a good challenge.

“About a year or so ago,” said Marc, “I had a good client in Texas send me a new Ruger GP100, a model 1789, for our ‘Ultimate’ Level 1 customization.”

“I was impressed,” explained Marc. “This model 1789 was already configured as a 7-shot .357, with the Novak Lo-mount rear sight installed. This meant no more time consuming Frankengun builds if I could start with one ready-rolled from the factory. Now I could customize a gun — instead of taking two to actually ‘build’ a single one.”

“When I received the customer-supplied gun for his build, I was unaware it was a new production offering from Ruger,” said Marc. “That being said, good luck finding one at the moment! Fortunately, I purchased this example from the savvy customer who sent its twin to me for his build. He was smart enough to buy two when he could, and was gracious enough to sell this one to me. I took that opportunity to do this build, based on the customer’s ideas for his own gun.” 

The Idea

Gemini’s “normal” build usually works around an “Ultimate” barrel Marc machines from a Krieger barrel blank. I’ve found a 3″ barrel length to balance well with the heavier Ruger revolvers and helps aiming due to the longer sight radius. There’s also a subjective feel I’ll call “pointability” seeming to be more comfortable with the 3″ guns. But in this case, Marc’s client was thinking outside the box.

“My client wanted something a little different than my typical configuration with our 3″ Ultimate barrel, explained Marc. “He wanted something shorter — nearer to 2″. He fancied, as he described it, ‘A 7-shot Belly Gun,’ so since I’m a custom shop — and the client is always right — I made it happen to his specs.”

The shorter barrel, Gemini Customs’ Exotic Wood grips, plating, tuning, etc. — all the good stuff and a few cosmetic details — came together in what you see here. This gun mirrors the client build, give-or-take, so you get a good idea of how brilliant the concept was to begin with. Short, fast, effective and lovely to behold. What’s not to like?

Dimensionally it’s not significantly larger than a small-frame 5-shot Ruger SP101, but has 7-shot .357 magnum capacity. That’s a good argument for a defensive revolver.

The hammer is centered and shimmed while the cocking spur serrations are cut at 25 LPI.

The original barrel is replaced with a Gemini Customs “Ultimate” 12-angle
profiled barrel after considerable effort to make sure the replacement is
lined-up and top-dead-center. Gemini Customs uses Armor Guard
“Copper” PVD plating for an eye-catching and practical accent.

The Build

Marc has a true engineering-style eye for machine work and it shows not only in his build quality but in the design of the features and the benefits earned from the ideas he incorporates.

In this build, Marc removed the original barrel, then line-bored and re-threaded the frame from 5/8″ TPI to 11/16″ TPI for the installation of a Gemini Customs “Ultimate” 12-angle profiled barrel. The term “line-bored” is critical here as it means Marc trues the “hole” in the frame to line up perfectly with the bore of the new barrel. You might be surprised to note that’s not normally done in a factory build. The frame is cast or machined, threaded, then a barrel is screwed into it and fitted. One might be a bit out of alignment with the other but “good enough” for production guns.

Marc then machined this custom short barrel from a Krieger large OD barrel blank. Picture a heavy steel piece of round bar stock with a precision bore drilled and rifled down the center. Mark machines these the old-school way with a lathe and milling machine — no hands-off CNC here — and a contoured barrel appears magically.

Prior to installation, Marc’s lathe turns the barrel throat at five degrees and polishes it, the lathe turns the muzzle crown at 11 degrees and “window cuts” the ejector rod slot. That cut looks good and can allow dirt and crud to clear from that all-important channel. He also cuts the dovetail for a Novak 65 x 0.300″x0.70″ front sight.

Only then does the barrel get installed to top dead center alignment, with the barrel to cylinder gap set at 0.006″ +/- 0.001″. It’s tight but not so tight as to bind if you’re shooting lead. Marc also cut his remarkable “V8 Hybra-port Porting” into the barrel with four ports on each side, angled “just-so.”

Marc administered Gemini’s “Mastergrade” extensive de-horning and smoothing for easier carry and surface prepped the revolver to 100-170 fine matte for the black PVD DLC plated finish.

We need to chat about the action on this gun. From personal experience I can tell you it’s tough to get a truly smooth, seamless DA trigger pull on a Ruger DA revolver. I can do it on an S&W, well enough to bring tears to the eyes of a revolver fan, but that sort of thing has always been just out of reach for me on a Ruger. Not so Marc.

His actions are smooth, effortless and virtually step-less, allowing a smooth, continuous DA pull until a delightful break of the sear. He sets the single action at 2.5 lbs., and the DA at 10 lbs. It’s precise, consistent and so addictive you’ll find yourself simply exercising your trigger finger for the sheer joy of feeling the action.

Just as importantly as doing the action, Marc installs an extended-length, custom-fitted firing pin. A lighter hammer strike on a Ruger often means the need for a longer firing pin and many (most?) leave this step out. Marc also shims the hammer, hammer dog and trigger to keep things centered and running smoothly. All the action components are coated in Armor Guard “Copper” PVD plating. A nice touch is the hammer cocking spur serrations cut at 25 LPI.

The trigger guard gets skeletonized, the ejector rod serrated at 25 LPI, there’s a full moonclip conversion (using TK Custom 7x.357 clips) and it’s all neatly plated in PVD Copper. While he’s at it, the chambers get finish-reamed, honed and micro-polished, charge holes get radiused and polished and the cylinder face is polished. Not a single detail is overlooked. Trust me on that.

I disassembled this gun down to the last pin and I saw things polished and carefully fitted I had no idea you could even polish, much less fit better. Want to see a master’s work? There it is right in front of you.

Novak 3-dot Tritium Night Sights also got installed, with a double white outline rear dot and orange outline front. Nice, bold sights, easy to see in daylight or at night.

The serious but attractive black and copper “Armor Guard” PVD DLC plated finish by Richter Precision is both elegant, businesslike and practical all at once. It reminds me of a black-on-black Bentley with a bit of bling here and there. There are seven colors available in this very high-tech Aerospace plating process so make sure you avail yourself of the options for your own build.

The final touch, the period on the build if you will, would be the Gemini Customs Gen II full-size 3F GP/SRH World Class Wild Olivewood grips. Say that three times fast, eh? They’re hand-built, hand-fitted and hand-bedded, then anointed with a hand-rubbed oil finish — all done by Marc. They look stunning in the photos but you should see them in real life, and better yet, feel them in your hand. They help to control any fire-breathing load you venture to tackle. All the while looking good doing it.

All of this keeps reminding me of the saying having to do with the sum of the parts being superior than the parts alone? Lord, this is a pretty gun.

With seven shots of .357 Magnum this wheelgun doesn’t lack anything in firepower,
making it a serious — and classy — choice for self-defense carry. Inside the guard
cutout is the 2.5-lb. single-action trigger which is so “precise, consistent and addictive
you’ll find yourself simply exercising your trigger finger for the sheer joy of feeling of the action.”


Let’s just say it — it was effortless to shoot and enjoy this gun. I shot it for accuracy at 20 yards (1″ to 1.5″ or so using my good glasses) and shot it over the chrono and it was a delight the entire time. The ports, while certainly noisy, do a remarkable job of reducing muzzle flip and felt recoil on even the most adventurous loads. I shot a 180 at just over 1,200 fps from this gun and it just went bang (really, really loud) but it was, dare I say it, fun to shoot. As a test, I fired the same load in a “non-ported” 4″ DA revolver I have and it was ugly. Yikes. The difference was huge.

A couple of .357 numbers to whet your appetite would be a Buffalo Bore load consisting of a 125-grain JHP clocking 1,367 fps; a Hornady 125 FTX at 1,207; a Federal 180-grain “Castcore” (a hard lead flat point) at 940 fps and a Federal 140-grain Barnes at 1,190 fps. All were controllable and accurate. I think the 180 Castcore load might just be a good field/trail and bear load as it’d penetrate like crazy no doubt.

In .38 Special, the gun is a real charmer and even more accurate. Black Hills 148-grain target wadcutters cut 1″ groups, or a bit under, at 20 yards and were addictive to shoot. Velocities were in the 620 fps range, about 25 fps less than the 4″ barrel. A 125 Federal JHP .38 Special delivered 980 fps from the short barrel. Overall, you lose maybe 50 fps or so going to the 2″ barrel from a 4″ but that’s meaningless in the real world

Packing impeccable mechanical operation into a fistful of power, the
Gemini Customs Ruger GP 100 is a sophisticated choice for serious carry.

Think About It

Over the years I’ve handled many guns from Marc’s shop and every single one has been, frankly, stunning examples of absolute top-tier quality, showing no compromises in build distinction. I don’t say that lightly, and would only say the same about a very tiny single-handful of ’smiths in the industry. Marc’s right there at the top with them.

If I were you, I’d seriously consider looking into getting yourself an “ultimate” custom revolver for your enjoyment — and protection.

Tell Marc we sent you, would you?

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