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Corvus Defensio AUG Case Deflector, an effective upgrade for all Steyr Arms AUG rifles

The Steyr AUG is a venerable assault rifle, that in spite of its futuristic looks and bull-pup configuration, has been designed in the late 1960’s. Since then, it has been adopted by many nations as their main assault rifle, including its native Austria. Semiautomatic versions of the Steyr AUG have been extremely popular in the past, and the gun is still available in multiple configurations on the civilian market in Europe and the USA. As futuristic as the AUG appears, some design features have not aged as well than others. Sure, the Steyr AUG has gone through many upgrades, and the current AUG A3 offers a lot of improvements; however, the ejection port design has remained the same of the STG77 as adopted in 1978.

Shooting tactics and doctrines have evolved since then. For example, changing shoulder to shoot around left and right-handed corners to take advantage of the cover and expose as little as possible of the body.

The Case Deflector partially assembled 
The Case Deflector partially assembled 
Corvus Defensio Case Deflector
The Corvus Defensio Case Deflector is made of four parts: the wedge shaped rear part, two T-8 TORX set screws and the front fork. 
Interaction of the parts composing the Case Deflector
Interaction of the parts composing the Case Deflector. A mild thread locking compound like Loctite 425 or mid strength Loctite 243 should be used on the threads.

The Steyr AUG has no provision for spent case deflection, and that’s all right – virtually all guns of the era did not either. However the AUG being a bullpup means the ejection port is just a few centimeters away from the shooters face. For lefties, a semipermanent solution is available – switching to a left-hand bolt and changing ejection port. But, if you try to switch shoulder to shoot around a left corner, what happens is the “AUG kiss” – the hot and fast spent case essentially slaps across your nose and mouth! Painful, indeed.

A technique is to place your non-shooting hand in front of your face when shooting southpaw, and it will deflect the cases. But then it’s not going to support the rifle. 

Corvus Defensio AUG Case Deflector on a Steyr AUG A2 SA rifle 
We used a Steyr AUG A2 SA rifle configured using an Aimpoint T-1 rig complete with a 3XMAG-1 magnifier mounted on a Flipmount and Twistmount base; a Surefire M300C Scout Weaponlight and LaserMax green laser aimer.

Corvus Defensio Case Deflector: how it works

Enter Corvus Defensio, an Austrian company that makes a range of very interesting accessories that focus on the Steyr AUG; many of these are compatible with every AUG built since the 1970’s, others are specifically designed for the latest A3 version currently available. The Corvus Defensio Case Deflector is compatible with all right handed .223 AUG rifles, and can be installed on the rifle with absolutely no modification to the gun, mounted around the right-side ejection port.

Shooting left handed with the AUG and the Corvus Defensio Case Deflector 
Shooting left handed with the AUG and the Corvus Defensio Case Deflector installed posed no problems at all. We never experienced even stray spent cases contacting exposed flesh, though looking at the images they seem to be uncannily close…

What this accessory does is to deflect ejected cases forward or to the side, adding huge flexibility to how the rifle is used, allowing the shooter to use whichever combat stance and either shoulder as needed. 

The Case Deflector is built from two parts of CNC milled billet 7075 alloy that is then hard anodized. Once slipped into the ejection port, two T-8 TORX set screws secure the accessory to the rifle thanks to two expanding opposing claws that grip the polymer ends of the port itself. The metal also protects the polymer stock from damage against the spent cases and specifically if an FTE (Failure to Eject) causes a stovepipe or other jam.

Corvus Defensio Case Deflector installed on the Steyr AUG ejection port
The Corvus Defensio Case Deflector installed on the Steyr AUG ejection port.
The Corvus Defensio Case Deflector forms a raised fence around the ejection port
The Corvus Defensio Case Deflector forms a raised fence around the ejection port that offers a slightly increased protection from blowback due to unburned powder and debris escaping the port and threatening our face.

The Corvus Defensio Case Deflector also does not reduce the size of the ejection window in any way, as it is completely external to the action of the gun save for the two “claws” grabbing the inside of the port.

The actual installation is extremely easy. Just remember to add some mild thread locker, such as Loctite 425 or mid strength, Loctite 243, to the screws so they do not come loose under the vibrations of the gun shooting. There may be minor adjustments necessary with few rifles, and it must be noted that this accessory is not compatible with NATO stocks or 9mm rifles.

Corvus Defensio Case Deflector 
The Case Deflector is built from two parts of CNC milled billet 7075 alloy that is then hard anodized.

Corvus Defensio Case Deflector: our test

We tested it on three different AUG rifles, and one -  an older A1 - has the claw of the accessory touch the face of the trunnion plate in which the bolt locks and that is at the breech of the AUG action when the action itself is assembled in the stock. All that was needed to allow the cross bolt to lock the action in the stock was a shim made of two overlapping pieces of aluminum adhesive tape, about 0.3 mm thick, placed inside the front hook. The Corvus Defensio Case Deflector is absolutely secure and stable in all conditions on this specific rifle, after this easy fix.

We finally mounted the Corvus Defensio Case Deflector on our own Steyr AUG A2 SA rifle, with outstanding results: spent cases never hinder the shooter, and it gave us a freedom of shooting stances previously unknown with the AUG! One thing’s for sure: this accessory is going to be a permanent add-on to our AUG.

The Corvus Defensio Case Deflector is available directly from the manufacturer at a price of 95 euro plus shipping, a very reasonable price for the quality and added functionality it gives the Austrian rifle.

The Corvus Defensio Case Deflector during a live fire testing at the range
The Corvus Defensio Case Deflector during our live fire testing at the range
Corvus Defensio Case Deflector during live fire test
The Corvus Defensio Case Deflector during our live fire testing at the range
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