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Corvus Defensio, a start-up company based in Vienna, Austria, focused on enhancing the Steyr AUG rifle platform. All founding members of Corvus Defensio acquired their own experience with this rifle when they were in military service. They liked the weapon a lot but wanted to come around some commonly known annoying gaps. In modern training and application due to its original design, the rifle lacks several features that are pretty standard with modern assault rifles and competition sport guns. Fast and reliable magazine changes, shoulder transition, a better trigger and proper light and laser mounting options are just a few of the things they wanted to improve. Now Corvus Defensio presents the first parts of their so-called “Steyr AUG Evolution Kit”. The majority of the new accessories is already in stock and ready to ship. Some items are currently in production and several more are in the final steps of development.

One of the first parts that were developed as a backyard project was the Enhanced Magazine Release Button. The original design is prone to malfunctions in certain situations. The Corvus Defensio Enhanced Magazine Release Button makes reloading faster and more reliable. When you go for the limit (stress caused by competition or combat, wetness, numb or cold fingers, darkness, etc.) faulty operations with the original magazine release button may happen. Your thumb could slip aside because of the original releases’ outwardly curved form or you even might not be able to push the button far enough inside the housing because your thumb was not right in the center of it and gets caught at the stock. The issue of the original part is that the release of the magazine happens just when the button is already recessed in its port. The design of the Corvus Defensio replacement part prevents those situations reliably, thus ensuring a faster and more reliable magazine change.

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The next thing they took care about was that the shooter should be able to fire the gun when transited to the support side shoulder. AUG owners had bad times when they joined modern rifle classes where they were taught to do so because a proper functioning AUG ejects the empty cases to the rear. Right into the shooters face. And this can not only distract but also hurt the shooter. Corvus Defensio came up with a patent pending design that is slick and protects the shooter as well as the plastic stock. The Corvus Defensio Case Deflector ejects cases forward or to the side and thus makes it ideal to shoot in every combat stance, from either shoulder, without any additional modifications or adaptations. Installation requires no drilling or modification to the stock as the two-piece Case Deflector is simply plugged into the ejection port and tightened with two screws, the plastic stock is also protected against damage when an empty case is not completely ejected.

Corvus Defensio also enhanced the interface system of the AUG. There is a trend for increased rail space on modern weapon receivers. Back Up Iron Sights, Optics, Magnifiers, Lasers, NVGs, Thermals, you name it. The original A3 receiver rail is rather short. So Corvus Defensio developed a 35-Slot Receiver Rail that offers a long, solid mounting solution for the attachment of all that aforementioned accessories.  The total length of the rail is the same as the rail length of an AR15 receiver and attached 9” (midlength gas system) railed handguard.  Unlike the AR15 receiver and handguard rails, the Corvus Defensio 35-Slot Receiver Rail is solid (monolithic) from front to rear.  Unlike the original Steyr AUG A3 rail, the Corvus Defensio Receiver Rail reaches almost to the ejection port, making it easier to use short eye-relief optics. It is equipped with two QD-Sling Swivel attachment points that give the shooter the option to quickly attach a rifle sling away from the gas port or the charging handle that caused trouble with the original forward sling mount. Additionally, the rail has an interface to directly mount ACOG rifle scopes without using any optic mount. This feature is meant to bring red dot piggy pack optics lower to the axis of the barrel if the shooter uses this kind of optical setups. At either front side of the rail there are Keymod Keyholes to mount Laser markers and weapon lights without interfering with optical sights.

Keymod is also the chosen standard when it comes to CorDefs Forward Accessory Rail that replaces the original vertical front grip.

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This Rail revolutionizes the Steyr AUG’s mounting options.  Very simply, it is attached on the mounting interface of the original folding front grip and enables the mounting of a variety of accessories directly to the Keymod interface (e.g. front grips, bipods, etc.).  Direct mounting reduces weight and bulk, but if you want to use common Picatinny mounts, you can attach the Corvus Defensio 15-Slot or 4-Slot Keymod-Picatinny accessory rail sections to the Corvus Defensio Accessory Rail. The rail is built-in a way that the disassembling of the barrel is still possible. The meaning behind the whole system with all its additional rails is to be able to mount a vertical front grip (straight or angled) as close as possible to the trigger guard. This simplifies a proper stance in unconventional positions or shoulder transitions while wearing body armor. Unlike to a conventional rifle, you do not have to grasp the AUG almost at the muzzle to control it. This is mainly to its different weight balance and ergonomics. With the fully equipped Forward Accessory Rail the shooter is able to mount lights and lasers to the rifle that can be activated by the support hand without leading trigger cables over the gas port. It’s also possible to additionally mount bipods for DMR use. The system is fully adaptable to the ergonomics of the shooter.

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Another problem the developers came across countless times while in the military was a twisted rifle sling.  Because the original stock cap retainer bolt can be rotated around its axis, the sling can become twisted after repeated slinging and unslinging of the rifle. The Corvus Defensio Anti-Rotation Stock Cap Retainer Bolt Kit solves two problems that often occur in this regard. The twisting creates unpleasant pressure points on the shoulder and quick adjustable slings might also lose that function.  While the Corvus Defensio Anti-Rotation feature completely prevents twisting of the sling, the QD function allows for fast sling detachment, e.g. for disassembly and cleaning of the rifle. The QD Pin can also be used without the Anti Rotation Device that is attached directly do the Trigger Pack. This Set-Up is currently in production and pricing and availability is expected soon.

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All that is good already. But one of the biggest concerns shooters have with the Steyr AUG (and Bullpups in general) is the trigger system and how it performs. The original plastic trigger feels a bit like a single stage trigger with a hard pull and a creeping reset. Corvus Defensio was inspired by the idea of Ratworx and 2020 Precision to implant a standard AR15 trigger into the Steyr AUG. As it was not possible to obtain one of these triggers in Europe CorDef started to design their own Enhanced Trigger System. It´s rather tricky to accomplish a proper technical solution with a reliable trigger system that fulfills the expectations. But Corvus Defensio is on a good way to get a solution using in their opinion one of the best AR trigger systems that can be found. Namely ALG and Geissele Triggers. The fine-tuning and the quality checks are still going on and the prototypes are very promising.

To draw the balance: Every part that we were able to test and evaluate solves problems that were existing since the weapon was introduced in the late 70s. Some of those problems were not striking back in the days. But in the modern application of rifles, there is a strong focus on the individual shooter. May it be in combat or in competition. And so it´s more important than ever that a rifle platform supports all users demands. Let´s see what Corvus Defensio comes up with next.