I admit it. I’m a gun nut. It doesn’t matter if they revolve or cycle, or if they load from the front, the back, or the bottom. It doesn’t matter if they hold a single cartridge or half a box full. It doesn’t matter if they’re made of blue steel and wood, or Tenifered steel and plastic. If they go “bang,” I love them.
So, when the Shooting, Hunting and Outdoor Trade Show (SHOT Show) rolls around every January, I feel like I’m getting a second shot at Christmas. As the show nears, the anticipation builds as I think of all the wonderful guns and people that I’ll be able to see, and just like the kid who dreams about the unknown possibilities that wait for him under the tree, my mind becomes preoccupied with thoughts of the exciting new products that will be unveiled at the show.
You can imagine my delight then, when Kimber introduced the K6s revolver to the shooting world at SHOT Show 2016. Not only was the gun tailor fit for a RevolverGuy, but it also came as an incredible, and highly unexpected, surprise.
This is the story of the development of this impressive revolver.
Little Package, Big Surprise
As 2016 dawned, the snubby revolver market had grown stale in many ways. Ruger had upset the market with its unique, polymer-steel-aluminum hybrid LCR revolver a few years before, but aside from that notable highlight, things had been pretty boring in the snubby world since the rollout of the new Centennial frame by Smith & Wesson in 1990. With the LCR’s big splash behind us, it looked like the snubby market was settling down and going back on cruise control for the foreseeable future. Kimber had other plans, though.
Now, if you had asked a crowd of RevolverGuys where the next new revolver design would come from, Kimber probably wouldn’t have made the list. Since their rebirth in the mid-90s, they had firmly established themselves as 1911 pistol and (going back to their roots) bolt action rifle manufacturers. A new hunting rifle or mini 1911 wouldn’t have caused a stir, but a revolver? That was an honest-to-goodness surprise.
Even better, Kimber’s new gun, the K6s, thumbed it’s nose at the snubby status quo and gave the market something it had been pining for since the demise of the once great, rampant Colt—a six round cylinder! It was immediately clear that Kimber wasn’t messing around, and a legion of gun guys—even the bottom-feeding heathens who had never been interested in revolvers—were suddenly excited about Kimber’s new design.
From Whence It Came
The K6s didn’t appear out of thin air, of course. A lot of energetic and talented people worked hard on the design prior to its release at SHOT 2016.
The K6s began in the minds of a few RevolverGuys who worked for Kimber. They were enthusiastic about producing a wheelgun with the Kimber logo on the side, but also wise enough to seek input from recognized subject matter experts outside the company.
One of those experts was Grant Cunningham, a highly regarded gunsmith who hung up his shop apron to focus on providing training and education to a rapidly growing population of self defense-minded shooters. As a specialist in the breed, Grant had a detailed knowledge of revolvers past and present, and particularly their inner workings. Furthermore, as a revolver enthusiast, and one of the few trainers out there offering revolver-specific classes, he had a unique insight to the qualities that were desirable in a defensive revolver. So, it was an excellent move for Kimber to approach him at SHOT Show and bring him aboard as a K6s consultant early in the project.
Grant made “more than one trip” to Yonkers to work with the design and engineering team responsible for K6s development, and found them highly receptive to his inputs. As a collection of RevolverGuys with a blank sheet of paper and a mandate to create the best defensive revolver possible, everyone brought their utmost to the table to make it a success.
That blank sheet of paper didn’t stay empty for very long with that much enthusiasm and experience in the room. At his first meeting with the Kimber team, Grant suggested four simple requirements for the new gun:
It had to be compact, to aid in concealment;
It had to hold six rounds;
It had to have excellent sights, and;
It had to have an excellent trigger.
The Kimber team had been thinking along similar lines, and their designers and engineers filled in the gaps. When Grant returned to Yonkers on a future visit to see the first prototype, he was immediately impressed with what he saw.
The new gun was definitely a Kimber. When Grant saw it for the first time, the lineage was clear. To begin with, all major components were made from stainless steel. Over the past decade or so, the industry standard had slowly shifted towards aluminum alloys, polymers, and exotic alloys made with light weight, high strength metals like Titanium or Scandium, but Kimber’s strength lay in forging and machining steel, so the K6s would follow suit.
The stainless steel format was the perfect choice for the caliber, .357 Magnum. Although the caliber hadn’t been specifically addressed in early planning, Grant admitted to being a little surprised to see the gun chambered in it, thinking instead that it would be a .38 Special. Going with the Magnum was a “Kimberesque” move though, as the company had already developed a reputation for building small powerhouses with its line of compact and subcompact 1911 pistols. The stainless construction of the K6s would help to tame the powerful cartridge, and ensure long term durability.
The lines on the gun were classic Kimber as well. Whereas snubby revolvers are typically a study in curves and rounded surfaces, the K6s looked positively angular and square. From the barrel profile, to the cylinder and frame flats, to the angular backstrap that flowed neatly into the rear sight, the gun had a look that was unmistakably Kimber. This is what a revolver made by 1911 guys looks like.
In size, the K6s compared favorably to its competition, approximating the size of its nearest competitor, the .357 Magnum Smith & Wesson Model 640. The K6s weighed the same, at 23 ounces, and was only .06” longer in overall length, and .05” wider than the 640. Despite the extra round in the cylinder, the K6s managed to be no bigger than its 5-shot rival.
The gun was built as a double action only, with no visible hammer spur. This had been the team’s direction from the start, and Grant was pleased that his personal preference for a “hammerless” design was shared. Grant knew the format had become de rigeur for concealed carry revolvers since the introduction of the improved Centennial-style frame by Smith & Wesson in 1990. All the major manufacturers had exposed-hammer designs in their catalogs for the traditionalists that couldn’t be without them, but the serious carry guns had all been hammerless (not just spurless, but closed frame “hammerless”) for over two decades at this point, and the K6s would be the same.
Interestingly, the early prototype of the K6s lacked a good “shoulder” on the backstrap, which allowed the gun to roll in the hand during recoil, particularly with the powerful Magnum ammunition. The collective team recognized the problem and changed the profile of the backstrap to include a more aggressive shoulder on later versions, above which the frame sloped upwards and blended nicely into the sights.
Ah, the sights. From the outset, the prototype had high visibility sights that gave an excellent sight picture, just as Grant had requested. The Kimber engineers designed a wide, ramped, front sight blade that was pinned to the barrel, not milled as an integral part of it. It was serrated and black, and easy to see through the generous notch of the black, serrated rear sight. The rear sight was dovetailed (a wonderful detail, offering great flexibility) into the frame in a manner that retained the sleek, no-snag lines of the gun. Legions of snubby fans who had strained for decades to see tiny slivers of front sights through shallow notches milled into the topstrap of their guns would instantly rejoice when they sighted in the K6s for the first time.
The gun would evolve and be optimized during the design phase, but the core essentials were there from the very start. From the moment he saw the first prototype, Grant knew it would become something special.
There are many choices that a design team needs to make when it creates a new firearm, and some of them have a great influence on other aspects of the design.
Take cylinder lockup, for instance. At present, there are three popular methods for locking up the cylinder of a double-action, swing out cylinder revolver. We’ll simplify things by calling them the Colt’s, Ruger, and Smith & Wesson methods, since each of these companies have typically used a different approach.
In the Colt’s method, the cylinder is locked at the rear only, with the tip of the spring-loaded cylinder release going into a recess in the ejector. There is no lockup on either the crane, or the forward tip of the ejector rod.
In the Ruger method, the cylinder is locked at the rear in a similar fashion, with the center pin lock going into a hole in the frame. However, there is also a spring-loaded latch on the crane that locks into the frame, which secures the front of the cylinder. Those of you who are students of gun history may recognize this feature from the vaunted Smith & Wesson “Triple Lock” (or .44 Hand Ejector First Model, or New Century—pick your favorite label). We’ll just call it the Ruger method for now, since they’re still using it as their primary method. Smith & Wesson has mostly abandoned it (we say, “mostly,” because the ball detent used in the X-Frame and the new “Combat Magnum” frames has some similarities).
The last method is the Smith & Wesson method, which locks the rear of the cylinder the same way, but also locks the front by means of a spring-loaded locking bolt that bears on the forward tip of the ejector rod. There is no locking mechanism on the yoke in this design.
Since they started with a clean sheet of paper, the Kimber team could have chosen any of the three methods. If they had gone with the Colt’s method, they would have needed to make the hand turn the cylinder clockwise, to help ensure the cylinder would stay aligned during recoil. It helps to turn the cylinder into the gun for added support when it’s only locked up at the rear, so the bolt locks the cylinder in place after the hand spins it clockwise into position.
The Colt’s method could have worked, but the .357 Magnum is a powerful cartridge for such a small frame, and the Kimber team was rightfully concerned about making sure the K6s cylinder was supported on both ends, so it was decided that they would choose another method.
The Ruger method actually provides the greatest support for the cylinder, with its frame locking lug, but the design is more complicated and expensive to manufacture (Ruger’s use of investment casting simplifies the process, and makes it less expensive than if the parts had to be forged and machined, as Kimber would do). Additionally, there is a possibility that debris can get into the front locking mechanism and prevent the cylinder from closing or locking up. Lastly, the design forces the frame to be a little wider, and the Kimber team was sensitive to keeping the gun trim.
So, the Smith & Wesson method would be used, with the ejector rod getting locked up on either end. This allowed Kimber to use a counter-clockwise rotation of the cylinder, but it also required them to ensure that the ejector rod would not unscrew and tie up the gun, which is a relatively common problem with the design. To prevent this, Kimber wisely used thread locking compound on the ejector rod threads, to prevent it from unscrewing.
The Smith & Wesson method also puts a premium on protecting the ejector rod from getting bent. Since the Colt’s system has no locking bolt up front, it’s a little more resistant to the effect of a bent ejector rod, and the Ruger is as well, because the ejector rod is offset, and doesn’t spin with the cylinder. In the Smith & Wesson locking system though, a small bend in the rotating ejector rod can prevent cylinder rotation, as the locking bolt binds on the tip of the ejector rod. As a result, an ejector rod shroud made sense as part of the barrel profile. Kimber could have used an exposed rod and a lug, as Smith & Wesson had been doing for almost three-quarters of a century on its J-frames, but the full shroud offered more protection and also gave the barrel a beefier look. The shroud has flats and angles that help to give the K6s a distinctive Kimber look.
Kimber had other choices to make inside when it came to the action. There was never a serious consideration of using a leaf spring to power the action, because coil springs are easier to work with (especially in a gun this size) and less expensive to manufacture, but the sear required a look.
In designs like the Colt’s revolvers, there is one continuous sear surface for double action mode, and a separate sear surface for single action mode. The effect of the continuous double action sear surface is to create a trigger pull that “stacks,” or continuously increases in weight of pull, as the trigger travels to the rear. Imagine a graph that plots trigger pull weight on the vertical (“Y”) axis, versus trigger travel on the horizontal (“X”) axis. A trigger that stacks will create an arc that starts at the origin, and gently curves upwards for a bit before it climbs sharply towards the vertical, at the end. While you can achieve an excellent trigger pull on such a design, the average shooter seems to prefer a trigger that doesn’t stack.
The alternative is to design a hammer with two double action sear surfaces, such as that found on Smith & Wesson revolvers. In this kind of design, the first three-quarters or so of the trigger pull happens on the first of the sear surfaces, and then you transition to the second sear surface for the remainder of the pull. On designs of this type, there is less stacking. In fact, on a typical Smith & Wesson J-Frame, the pull weight steadily increases to a peak on the first sear, and drops off rather quickly in the last part of trigger travel, just before the hammer is released off the second sear (those of you who “stage” your Smith & Wessons in double action understand). Imagine our weight-travel graph looking like a cane, with a linear increase in pull weight until the sharp downward curve at the end.
The Kimber team didn’t want their trigger to stack, but they also didn’t want their trigger pull weight to peak as high as a J-Frame, then fall off. They wanted a more linear trigger, with a pull weight that stayed more consistent throughout the trigger’s travel—more like the first part of the Smith & Wesson graph, prior to the drop off, but shallower.
They achieved it on the K6s with some changes to the geometry of the sear, hammer, and hammer strut. The K6s trigger is more linear than others in this class of guns. Pull weight builds slower and doesn’t peak as high. It’s a smooth pull of about 9.5 to 10.5 pounds that shooters typically report as feeling lighter.
The Kimber team gave special attention to many other areas of the gun, as well.
From the very first prototype, the trigger face was rounded and smooth, without grooves. This allows the trigger finger to roll across the face as the trigger travels to the rear, instead of dragging on the trigger and pulling the gun off target. Grooves were popular on wide target triggers back when single action fire was the norm, but on a double action trigger, you need a smooth, narrow surface for best efficiency, and that’s what Kimber chose for the K6s.
The choice of cylinder release was another area for the team to optimize the design. The traditional Colt’s release (which is pulled to the rear) and Smith & Wesson release (which is pushed forward) were eschewed in favor of a push-button style, similar to the Ruger standard. This style of release is Grant’s favorite, and it pleased him to see that Kimber chose it, as he feels it is easiest to manipulate. It works well for either a right or left handed shooter, and even works well when the shooter is doing one-handed manipulations. Shooters with large hands will appreciate the smooth button with its protective fencing and lack of sharp edges, because the thumb knuckle won’t get cut to shreds by the latch—a frequent occurrence for this writer when shooting J-Frames, even when they’ve been dehorned.
Speaking of dehorning, the K6s is interesting in that it’s designed to look angular and square, but the gun’s surfaces are all rounded to prevent getting bit. I don’t know what kind of magic they’re using to pull it off, but the effect is both appreciated and perplexing at the same time. Grant reports this is one of the details that was good-to-go from the very start, with the first prototype.
The excellent, high-visibility, user-replaceable sights on the K6s are regulated for 158 grain .357 Magnum ammunition at a nominal distance of 15 yards. There was a time when Smith & Wesson regulated their J-Frame sights for much longer (and optimistic) ranges, and Colt’s appeared to not regulate them at all, so this kind of attention to detail will be appreciated by RevolverGuys.
The Wheel Turns
Perhaps the most interesting bit of engineering on the K6s though, is the cylinder. It was decided at the very beginning that the K6s would be a six-shooter, as God and his good friend Colonel Colt intended. The extra round may not sound like much to our self-chucker brethren, but 6 rounds of .357 Magnum or .38 Special in a J-Frame-sized gun has been the Holy Grail of snubby fans for the better part of a century. If the feat could be accomplished in the K6s, it would guarantee the gun’s success.
Once upon a time, Colt’s had made a series of highly successful 6-round snubbies, based on the Police Positive-sized D-Frame. The famous Detective Special led the pack, starting in 1927, with the aluminum-framed Cobra (introduced in 1950) and Agent (introduced in 1955) models filling other niches. By 1995, Colt’s had discontinued the old D-Frame and replaced it with the stainless SF-VI frame, with virtually identical dimensions. The SF-VI and (identical, except for markings) DS-II snubbies carried the torch for a few more years, but by 1999 both they and the short-lived Magnum Carry had been discontinued as Colt’s abandoned the commercial market to chase military contracts. Suddenly, there were no 6-shot, small frame, .357 bore snubbies in production.
That suited rival Smith & Wesson just fine. Their smaller, 5-shot, J-Frame snubbies had been top sellers for the mark since 1950, and Colt’s exit from the market guaranteed them the lion’s share of the action. Shooters bought the various J-Frame incarnations by the truckload, but many sorely missed the 6-shot Colt’s cylinders. The Smith & Wesson guns had the advantage of being smaller than the Colt’s guns, but losing that extra round was a tough price to pay for a lot of folks.
So, it was critical to the Kimber team to marry the popular 6-round cylinder without deviating much from the outer dimensions of S&W’s flagship defensive snubby, the Model 640. Could it be done?
Yes it could. The Kimber team started by offsetting the location where the bolt comes out of the frame to lockup the 6-shot cylinder. This was necessary to maintain the integrity of the cylinder walls, particularly with high pressure .357 Magnum ammunition.
Consider a gun where the bolt window is located in the bottom center of the frame. When the cylinder is in battery, the bolt rises up from the 6 O’Clock position to engage the notch in the cylinder and lock it in place. If the cylinder is a 6-shot cylinder, then that would place the bolt notch directly over the center of the chamber, where the walls are thinnest. This creates a potential structural weakness—a place where high pressure gas could rupture the cylinder wall and escape.
You could solve this problem by increasing the diameter of the cylinder, to ensure that enough material remained after you cut the notch on the outside to safely contain the pressure, but that would require a bigger frame as well. Your small frame would grow larger and the gun would get heavier, to boot. Not ideal.
So Kimber took another approach, and shifted the bolt window outboard on the starboard (right, for you non-nautical types) side. By offsetting the bolt that direction, the notches on the cylinder could be moved so that they wouldn’t fall directly on top of the chambers. Instead, the notch could could be cut over the web that separates adjoining chambers, where the cylinder walls are thickest. This allowed Kimber engineers to safely contain Magnum-level pressures in a cylinder with the smallest outer diameter.
Going one step further, Kimber milled flats on the outside of the cylinder, which reduced the outer diameter. Instead of being a perfect circle, the cylinder now had more of a soft, hexagonal shape. The flats reduced the width of the gun at the point where it’s normally fattest, giving the 6-shot cylinder of the K6s a width on par with the 5-shot S&W Model 640 (1.39” versus the S&W’s 1.31”), as well as an identical weight (23 ounces). Kimber had built a 6-shot J-Frame!
To add icing to the cake, Kimber recessed the chambers, which came to be viewed as a premium feature, or a mark of Old World craftsmanship, after Smith & Wesson discontinued the practice on centerfire revolvers in 1982. Recessed chambers had their origins in the original Smith & Wesson .357 Magnum (the premium gun in the catalog), and were thought to be a necessary safety feature for the then-new Magnum cartridge in 1935. Time would prove the feature to be unnecessary for most centerfire revolvers, but the recessed chambers of the K6s feel like an upgrade and give the gun a cosmetic edge that contributes to the aura of a premium product, which plays directly into Kimber’s marketing strategy. As a practical matter, the recessed chambers did not require an increase in cylinder window length, allowing the K6s to maintain an identical overall length as the S&W Model 640 Pro (6.62” long, versus 6.6” for the factory semi-custom S&W).
Kimber K6S: Pocket Perfection?
When Grant was first approached by Kimber to consult on the development of the K6s, he realized it was an exciting, perhaps once-in-a-lifetime, chance to help create something special. So, the question is, after all the effort, is he happy with the final product?
“Absolutely,” he told me. He was “honestly surprised” with how good the first prototype was, and “was struck by the fact that the Kimber team had done a wonderful job of incorporating my inputs, while bringing some of their own ideas and sensibilities into the project.” The design only got better after that initial prototype, as the team refined it into the product we know today.
Kimber “has shown good consistency in production” and has exhibited a high degree of quality control on the K6s line, according to Grant. The samples he has seen come through his classes in the hands of his students have been absolutely reliable, with no breakdowns over the course of two days’ worth of high volume training.
He’s pleased with what he sees in the K6s, and if Grant is happy with the result, that says a lot. The Combat Tupperware crowd may not understand all the commotion over a 6-shot gun that runs in circles, but RevolverGuys understood from the beginning that there was something special about it. Hopefully, now that you know the story of it’s design and development, you’ll have an even greater appreciation for the K6s, and for the hard work and talent that went into creating it from a blank sheet of paper.
RevolverGuy would like to thank Grant Cunningham for his generous time and assistance with this article. Please visit his website at http://www.grantcunningham.com for more information about his training courses and workshops, his outstanding books and podcasts, and his highly entertaining and educational blog. We would also like to thank Thomas Finch of Kimber, who served as part of the K6s development team at Kimber, for the insight he provided into the design and manufacture of this revolver.