NEW FOR 2014
As many of our customers have known for some time, we have been working on a brand new product line, the fully Integrated Cantilever Base Mount (ICBM). We started this project back almost two years ago and as things progressed in the design and implantation, we ran into some things that we weren’t too pleased with.
Initially, we were approached by a defense contractor who requested us to design and build a fully integrated ring and base mount, specifically for the M4 / M-16 Flat Top platform. Furthermore, this platform build would not only be supporting a 30mm Day Optics, but would also be supporting a Simrad Light Intensifier.
To make matters worse, this entire system had to be built to withstand the abuse of a direct ground impact from 5 meters to simulate units being dropped from service members during parachute deployment.
As we began the design process based upon the benchmarks that had been set, we ran into several bumps along the road. For one, we were highly constrained on delivery and pricing. Obviously, in our business the customer want’s it yesterday and cheap, maybe even free if you will do it. Due to the time constraints in which we had to produce this new product and for the price requested, we opted to begin the Testing & Evaluation (T&E) based upon using 6061-T6511 aluminum alloy. Since just about everybody in the industry who was building a similar product was utilizing 6061-T6 alloy, it seemed to be the thing to do, and of course, anymore, you can buy the 6061-T6 aluminum at your local box store.
We’ll, with that established, and 22 months later, we unveil our new product that we are proud to put our name on. As you know and can imagine, we were unable to provide this product to the defense contractor in the time frame and cost that they were expecting. The further we got into this project, we began to realize that meeting the rigorous requirements set forth in the initial product design was completely unobtainable utilizing the selected 6061-T6 aluminum alloy. It’s easy to get at your local hardware store, inexpensive to purchase and machines beautifully, but the strength of the material would not come close to meeting the strength requirements of a Cantilever mounting system designed to hold the weight and maintain the accuracy needed for mounting optics to a precision firearms platform.
When we finally reached an impasse to this project deadline, we basically mothballed the project for almost a year. But, like many things we do here at TPS, we continue to work on projects in the back room, always striving to accomplish and succeed at everything we start out to do. Well, obviously we figured it out, but learned a lot along the way, and hopefully our perseverance will benefit you, our customers, in what we think is the finest cantilever designed mount currently in existence today
ONE OF THE MOST DIFFICULT ASPECTS OF THIS INITIAL PROJECT WAS OUR FINDINGS THAT THE MATERIAL ALLOY, 6061-T651 WAS NOT STRONG ENOUGH FOR THE JOB AT HAND.
The graphical illustration of the mount below is a color graph of the stress loads on the mount when 6061-T651 aluminum was used. An equal amount of force was applied to both the front and rear scope ring mounts. However, as you can see from the color spectrum, the entire front ring mount gives away, completely deforming, thereby not distributing the applied load against both the front and rear ring mounts. If you were to have your optics mounted in this scenario, your scope tube would be allowed to deform and flex over .020” (20/1000). The lenses inside of regular rifle scope will typically immediately or prematurely fail when more than .005” (5/1000) is exerted over a span of 4 inches. The image was created using a 150 Pounds per Square Inch (psi) at a velocity of 32 Feed Per Second (FPS) at 7.5 Meters, evenly distributed between the front and rear features.
The graphical illustration of the mount below is a color graph of the stress loads on the mount when 7075-T6511 aluminum was used. An equal amount of force was applied to both the front and rear scope ring mounts. As the color spectrum represents, the applied load was equally distributed over both the front and rear scope ring mounts. Because the material provided adequate strength for the conditions, it allowed the rear ring mount to almost equally share the impact. Although not perfect force transference, it did allow almost 95% distribution between the two ring bases. In this case, using the same data as above, the front mount distorted a total of .0018” (18/10000), a difference of over 1100% less flex than its predecessor. Although the mount also distorted under this case study, it was well within the acceptable standards set of .005” maximum distortion. The image was created using a 150 Pounds per Square Inch (psi) at a velocity of 32 Feed Per Second (FPS) at 7.5 Meters, evenly distributed between the front and rear features.
NOTE: THE ABOVE DESIGNS WERE DEVELOPED USING FINITE ELEMENT ANALYSIS (FEA) TO OBTAIN THE HIGHEST STRENGTH DESIGN POSSIBLE WITHIN THE DESIGN CONFORMITIES ALLOWED.
Obviously, as all our customers know, we manufacture all of our aluminum scope rings and rails from 7075-T6511. But, we also order our material 12-14 months in advance so that we can maintain ample stock for production, since you can’t but this stuff at your local box store. And we also buy this material in very specific sizes for the product line that we produce, so to acquire an entirely new material size for a new product takes a long time, like about 12-14 months. To produce this part takes a solid billet of material that is 2” x 2” x 7” long, for you math wizards out there, that about 28 cubic inches of material. And for you accountants, that is a lot of money just in the raw material before you start.
By going to 7075-T651 compared to 6061-T6, our material cost increases by almost 250%, and we have to buy very large volume just to obtain that pricing, otherwise we would be looking at over 500% material cost difference, which would make it virtually unobtainable for our customers.
As you can quickly imagine, making this new mount from your local box store 6061-T6 would have been quick and easy but it wasn’t a direction that we could or would follow. During the course of the year, we went through multiple design studies from the cost of manufacturing to the ultimate strength issues that relate to what a cantilever mounting system must be able to do.
We are extremely familiar with strength issues as it relates to optical mounting hardware, since we started the 7075-T651 aluminum alloy revolution almost 15 years ago. We realize that our scope rings are extremely overbuilt for most of the applications in which they are used, except for mounting on 50 BMB and 20mm platforms, in which it’s the only material that will withstand the punishment. However, when we began running Finite Element Analysis (FEA) which provides the designers and engineers to determine the proper design, features and material to perform the tasks required, we quickly realized that 6061-T6 was completely incapable of the strength required on the cantilever mount.
Using an Ultra-high strength aluminum alloy such as 7075-T61 was not just a good thing, but an absolute requirement for this application. By its very design, a cantilever is exactly that, a lever. We are attempting to increase the height of the optics mounting platform above the rail of an M4 rifle and push it forward to obtain increase eye relief. By doing so, you are extending the entire system out on a less than ideal support platform and all the weight of the combined optics and kinetic energy is being “leveraging’ from the mount. Without an outstanding strength design in that cantilever you have hanging out, unsupported, you will experience a large amount of movement, flex, twist and immediate or premature failure of your optics attached, at the very least.
Not to even touch on the drop test in this conversation, the amount of stress exerted on the cantilever mount alone during recoil of a rifle was astounding, one of which we initially didn’t realize until further development studies. The good news, with proper material selection and engineering, we have accomplished the goal we set out to do, build a fully Integrated Cantilever Base Mount (ICBM) that can withstand the not only the standard punishment of recoiling rifles, but also accidental stresses from direct impacts from dropping the weapon platform on the ground.
As we moved forward with this project, we continually worked with and consulted military operators in the field, obtaining ideas and input as to a better design in the end. One of the major request that we have received is the ability to have this mount available in a variety of Minutes of Angle (MOA) capability. The second, was having the product selection available in 1 Inch, 30mm, 34mm and 35mm optics.
We have designed and prepared to make available all of those models in the coming year of 2014. Our first product off the line is our 30mm mount in 0 MOA. Quickly following will be the 1 Inch and 34mm Mounts in 0 MOA. By mid-year 2014, we will have available all of the mounts in all sizes and MOA’s in 0, 20 MOA and 30 MOA.
We sincerely appreciate the patience that so many of our customers have provided us in the development of this latest product line. We feel confident that once you have the opportunity to have this mounted on your M4, you will be glad you waited as long as you did and so will your optics that is attached. As you may wonder about the naming of this mount, which we have received numerous inputs, we opted to go with ICBM, with all good humor intended, it’s a direct nuke attack on the competition.