If you were at the Knob Creek machine gun shoot in spring of 1999, you might have met Marty Daniel, the owner of Daniel Defense. He shared a folding table with one of the other vendors and had a small, hand-lettered placard that read, “Ask me about my tactical sling loop.” More than a few people did, and considering the burgeoning AR-15 accessories market, he decided to devote his attention full-time to the tactical gun parts business. Shortly after his appearance at Knob Creek, Marty began developing an entire line of rail systems called the Daniel Defense M4 Rail. At that time fore-end rail systems were being issued to most units under Special Operations Command (SOCOM) and a handful of elite infantry units, but had not yet found much following in the civilian shooting sector.

railproduct.gifThat began to change, in large part due to the efforts of Daniel Defense, and five years later there were a couple of companies offering railed fore ends for commercial sales. Around this same time, there were rumors floating through military- procurement circles that SOCOM was interested in upgrading its Special Operations Peculiar Modifications (SOPMOD) package to bring the M4 weapon system into the 21st century. The rumors came true later that year when Naval Surface Warfare Center Crane, who would manage the program, issued an open solicitation for a free-float railed fore end to replace the existing legacy system. At the time the solicitation came out, Daniel Defense was still technically a one-man show. Marty would occasionally have friends or family help pack boxes, but he was the only full-time employee on the books. He also had some very good partnerships with other folks in the industry that helped some with designs and marketing and he knew that he would need additional help navigating the military procurement process. He started by taking advantage of some state programs for small business initiatives and from there began hiring some very talented folks from throughout the industry to help out.

Simple in Concept
The Crane RIS II Solicitation had at first glance what seemed to boil down to a couple of simple requirements: Free-float the barrel and free-float an M203 grenade launcher. Daniel Defense took the requirements, but also understood emphatically what the operators really wanted. In addition to the original requirements, the Daniel Defense RIS II also increased the useable rail area by almost 50% and provided a monolithic top rail for uninterrupted mounting of optics, lasers, etc. Anotherrailcut.gif hurdle to overcome was the color. Long gone are the days of blued steel and walnut: The solicitation required that the Rail System be finished in FDE (Flat Dark Earth) tanish/greenish/brownish color, that is a good fit for many different types of environment. Unfortunately, it is very difficult to Type-3 hard-coat anodize to military specification in this color. Daniel Defense initially tried some alternative coatings, but could not achieve the necessary hardness required for long term-durability. After collaborating with some of the best metal chemists in the industry, they were finally able to crack the code and produce the rails with a mil-spec anodizing in FDE.

After two years in testing and development, Daniel Defense was finally awarded an IDIQ (indefinite delivery, indefinite quantity) contract in 2005, to provide 30 sample rails for testing and evaluation. With the start of operation-and-developmental testing, it was time for the end users to have their say. The RIS II submission was pitted against the other two competitors, KAC and A.R.M.S., in a competition that lasted nearly two years. Rails were carefully tested to determine their durability, ability to retain zero, modularity, cost effectiveness, and other factors. After being shot by hundreds of operators from every branch of service, the long, difficult battle was over and the Daniel Defense submission was declared the winner in fall of 2006.

Improving the Best
The story doesn’t end there, though. No sooner had the ink dried on the RIS II contract before engineering changes were submitted by Crane so that Daniel Defense would actually provide a family of rail systems for the many different variations of the M4. There is now a 10” version specifically designed to work with the 10.5” barrel of the Mk18 CQBR, an 11” version for rifles with 12.5” barrels called the GL/SSC, and the 12” RIS II designed for any rifle with a barrel longer than 14.5 inches including the M4A1, M16A2 and Mk12 SPR. Among all three rails there is about 90% parts commonality and they all have the removable bottom rail for mounting and free-floating an M203 grenade launcher. The removable bottom rail is attached with four screws that are held in place with a small self-locking helicoil. The Daniel Defense RIS II mounts to the upper receiver, utilizing the “Bolt-Up System” that locks the rail system solidly around the proprietary barrel nut. There are two reserve stops on either side of the rail-locking collar that, along with the Bolt-Up System, and the gas tube, prevent the possibility of any rotation after the rail is properly mounted. The NSN package is rounded out with a variety of soft polymer rail covers of varying styles and lengths to cover and protect unused portions of the rail. Installation of the RIS II is as simple as swapping out a barrel (relatively easy for the M4/M16 family of weapons) and can usually be accomplished in about 15 minutes.

Daniel Defense is currently shipping these rails out daily to Crane, where they are fitted by Crane armorers to existing weapon systems, repackaged with the rest of the SOPMOD Block II components, and then returned to the unit as a nearly new weapon kit. It’s a total system upgrade that has been nearly 10 years in the making and should carry the SOPMOD program through the end of the weapon’s expected service life. In addition to being available through Crane and the military supply system, these rails are available for commercial sale direct from Daniel Defense or from one of their authorized dealers. It has been a long, bumpy road, but after four long years the Goliaths have been out flanked and there is a new king of precision rail systems. For more information visit


The Omega Rail
While there are many two-piece rail systems on the market that can be installed by the user, most of them share some common problems: The most obvious is that they are not free-floated. This means that when various accessories are attached to the rail system (like a sling, fore grip, or bipod) they can apply stresses to that system, which can affect the impact of the bullet by applying imperceptible movement to the barrel. The few available systems that are free-floated, require the user to make alterations to the weapon configuration–sometimes even having the user to cut off various components to allow for proper installment. As is one of their strengths, Daniel Defense has again listened to the end users and devised a rail system that is both free-floating and easily installed by the user, with no modification to the host weapon. The Omega Rail uses a modified version of their Bolt-Up System that applies tension to the standard barrel nut without interfering with any other components. In addition, it has a monolithic top rail for the uninterrupted mounting of optics and aiming devices.

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