Windham Weaponry’s 5.56mm CDI comes with plenty of high-quality accessories to keep LEOs in the fight. Shown topped off with an EOtech EXPS-2-2 with G33 3.25X Magnifier.

In recent years, the AR rifle has become nothing if not versatile. The advent of multiple aftermarket options has made this now-classic rifle easier to use and more accurate, compact and ergonomic than ever before. A well-equipped AR can provide the patrol officer with an adjustable length of pull for use with body armor or heavy winter clothing, an enhanced grip and triggerguard for use in inclement conditions or with gloves, and an incredible amount of space for easily mounting day and night optics, lasers, vertical or angled grips, bipods and tactical lights.

Budget- and litigation-conscious agencies may be reluctant, however, to invest in aftermarket parts and allow officers to tinker with their duty rifles. Fortunately, some rifle manufacturers are willing and able to deliver a complete rifle package with the best and most popular features already factory-installed. This helps such agencies save a lot of money and avoid liabilities from incorrectly installed parts.

The CDI’s low-profile, flip-up Diamondhead front sight has a distinctive diamond-shaped design that draws in the user’s eye

Windham Weaponry is one such manufacturer and has already secured law enforcement contracts. Their new CDI, a semi-auto, direct gas impingement AR, is a complete package delivered with the best upgrades currently available on the market. The name Windham Weaponry may be new to some, but it represents the rebirth of a famous factory that had lain dormant for several years following a corporate relocation. With a new name and the return of an experienced and dedicated workforce, Windham Weaponry is once again producing high-quality rifles.

The free-floating, 10.25-inch-long Diamondhead V-RS handguard allows operators to mount Picatinny rails where needed for add-ons.

Gun Details
The CDI’s low-profile, flip-up Diamondhead front sight has a distinctive diamond-shaped design that draws in the user’s eye.

Like most of its existing product line, the CDI is also an M4-style semi-auto carbine chambered for 5.56mm NATO. The biggest extra that comes standard on the CDI is the Diamondhead V-RS X handguard, which is 10.25 inches long, free-floating and quad-rail-ready. Not only does this system free-float the barrel, relieving stress on the barrel and improving the rifle’s accuracy potential, but it also provides over 16 inches of uninterrupted Picatinny rail space on top of the rifle when combined with the flattop receiver.

This much rail space makes for the easy installation of more advanced optics, including night vision and thermal extenders, as well as top-mounted laser units. The modular handguard also makes it a simple matter to add rail extensions where the operator needs them while leaving the rest of the handguard bare, keeping weight down, decreasing the dimensions and girth of the unit and improving the operator’s comfort. The handguards also come standard with a sling-attachment point at the bottom front and a substantial length of Picatinny rail pre-installed underneath.

Atop this handguard and flattop upper receiver, Windham Weaponry has added Diamondhead’s Diamond flip-up front and rear sights with their distinctive diamond-shaped patterns. These black anodized, stainless steel and aluminum sights firmly lock into place when needed and fold conveniently out of the way when using optics. The sights are fully adjustable for windage and elevation, and the diamond-shaped aperture makes for very fast and intuitive target acquisition.

The 16-inch, chrome-lined barrel has an M4 profile and is made from mil-spec 4150 chrome-moly-vanadium steel, which has a higher carbon content and adds significant strength and durability—both very desirable features in a duty rifle. The barrel has a fairly standard 1-in-9-inch twist rate, which does a good job of stabilizing a wide range of bullet weights, including very low-weight rounds intended for specialized uses.

Another upgrade to the CDI is the addition of the very effective Smith Enterprises Vortex flash suppressor. The four-pronged, open-ended device features a right-hand, 15-degree helical twist that increases its structural rigidity and ensures the unit will stay on the rifle. This device also almost completely eliminates muzzle flash and is compatible with blank-firing adapters for training purposes. The Vortex also accepts any of Smith Enterprises’ quick-detach sound suppressors. The reduction of flash helps officers preserve night vision during late-shift encounters.
Windham has built this rifle tough and to military specifications. At the back of the chamber are M4 feed ramps that are cut wider and lower than those of ARs and are designed to improve reliable feeding of rounds from the magazine into the chamber. This can be especially important for officers who need absolute reliability under less-than-ideal conditions where dirt, grime and moisture may be introduced. The bolt and bolt carrier are made from Carpenter 158 steel, and both are HP (high pressure) and MPI (magnetic particle inspection) tested. Most manufacturers will perform HP tests, but few bother with MPI testing, which is only required of true mil-spec bolts. This consists of using a magnetic field to detect any imperfections in the surface or subsurface of the part, ensuring that only the highest quality parts are being used.

Windham Weaponry manufactures the upper and lower receivers from forged 7075 T6 aluminum, and the rifle’s controls are in familiar places.

The bolt and bolt carrier are both phosphated and chrome-lined, and the bolt carrier has a mil-spec M16 contour (as opposed to a commercial-pattern bolt) that is stronger and heavier to ensure longer and more reliable operation. It’s also paired off with a standard carbine buffer. The gas carrier key has also been properly staked, which is especially important in a duty rifle since screws that are not properly secured can come loose under fire. Of course, all manufacturers will stake their gas keys in some way, but a sure sign of quality is a properly staked gas key that shows that a hammer and punch have been used with enough force to move sufficient metal into the carrier key screws.

Both the upper and lower receivers are manufactured from forged 7075 T6 aluminum and feature a well-applied, black hardcoat anodized finish. The controls on both the upper and lower receivers (dust cover, forward assist, bolt release, magazine release, charging handle, safety selector) are all located in the familiar places. None of the controls, except for the trigger, are ambidextrous. The standard location of the controls can expedite and ease officer training, and it can help maintain consistency across agencies. The triggerguard is a fold-down, aluminum-type for use with gloves.

Windham has added ambidextrous sling-attachment points at the rear of the receiver extension. The standard mil-spec furniture has also been upgraded with the addition of the extremely popular Magpul MOE six-position collapsible stock. This unit allows for easy length-of-pull adjustments so operators of all sizes (or those wearing heavy clothing or body armor) can utilize the weapon. The stock also provides a more compact profile for easier transportation in the collapsed position. The back of the MOE stock has a 0.3-inch rubber buttpad for a secure shoulder engagement. The adjustment latch is protected by the stock’s design to prevent inadvertent adjustments, and there are two sling-attachment points and a lanyard hole. Having used this stock extensively, I can attest to its high degree of comfort.

The lower receiver also features a Magpul upgrade, an MOE pistol grip, which has a very comfortable, ergonomic design with texturing that helps keep it in the hand even in harsh conditions. This tough polymer grip also has storage capabilities for extra batteries or spare parts. Finally, the CDI features the Magpul Angled Foregrip (AFG) under the handguard, which I far prefer to vertical foregrips. Using an angled design allows the shooter a more natural handhold that can improve weapon control.

The mil-spec, single-stage trigger broke very cleanly at just over 7 pounds with almost no creep, which is better than most standard AR triggers. For precision work, I might prefer a lighter trigger, but as a duty rifle it was perfectly serviceable. The fit between the upper and lower receivers was excellent, with only the slightest amount of play between the two. The black hardcoat anodized finish was also very well executed and attractive in what is sure to become a popular addition to the Windham Weaponry line. Even with all the extras, the rifle still weighs barely over 7 pounds empty, which is not much more than a stripped AR carbine. The added features make the rifle very easy to handle.

Windham Weaponry ships its rifles in a very durable, black hard-plastic case with a 30-round magazine, a sling and an illustrated operator’s manual with detailed information to keep the rifle running at its best. The company’s cursive logo is prominently displayed on the left side of the CDI’s lower receiver and on the magazine floorplate.

Range Time


I have had the opportunity to test several Windham Weaponry rifles over the past year, and I have been duly impressed with them. On the range, the CDI performed like a champ over several days of testing. Using a mix of ammunition, the rifle performed right out of the box with no maintenance and not a single malfunction of any sort.

For accuracy testing, I used a benchrest at 100 yards and mounted the Trijicon 3-9×40 TR20-2 AccuPoint scope with a mil-dot crosshair reticle and an amber dot. The variable power allows a shooter to have a wider range of view for observation and then easily zoom in for targeting. Without batteries, the excellent fiber optics on the Trijicon scope gather ambient light to illuminate the center amber dot.

The final results were between 2 and 3 MOA, which is certainly respectable and well suited for a duty rifle used at distances typically encountered in law enforcement engagements.

Windham Weaponry is indeed gaining acceptance among law enforcement and was recently awarded a rifle contract to equip Maine’s Department of Inland Fisheries and Wildlife. With the new CDI rifle, Windham Weaponry is sure to continue gaining in popularity. For more information, call 855-808-1888 or visit

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Windham Weaponry's 5.56mm CDI comes with plenty of high-quality accessories to keep LEOs in…