/ forgottenweapons
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The DeserTech MDR ("Micro Dynamic Rifle") has been in the works for several years now, after being initially announced at SHOT Show in 2014, if I recall correctly. While it was probably prematurely unveiled, the rifle as it stands today looks to be remarkably well designed. It is one thing to design a concept that sounds attractive (fully ambidextrous bullpup rifle convertible between 7.62x51mm and 5.56x45mm), but it is a whole other thing to actually develop a mechanical design that actually works. And it is yet more notable to make that system elegantly simple and to actually transition from handmade prototypes to successful production line manufacture. DesertTech appears to have cleared all those hurdles...
At the heart of the rifle is a rotating bolt locking system and a short stroke gas system. These are both very well understood systems - DesertTech has chosen to use proven ideas here instead of getting "innovative". The most interesting mechanical element is undoubtedly the ejection system, which can be swapped to eject from either side of the rifle but can actually be used from either shoulder regardless because it ejects cases directly forward. The system uses a pair of arms that push an empty case (or live round) laterally off the side of the bolt face and into a holding clip. A lug on the side of the bolt engages those arms on its rearward stroke, and a matching lug on the opposite side pushes the case forward and out of the rifle on the bolt's forward stroke. While this system sounds complex, the parts appear to my eye to have gone through a lot of testing and revision, as they look pretty simple and sturdy - a refined implementation of an unorthodox idea.
The controls are all ambidextrous, with non-reciprocating bolt handles, safety selector, and magazine release on both sides. A secondary magazine release is located on the front of the magazine well to allow a positive magazine removal, and this catch is stiff enough to not have problems with accidental release like some other bullpup designs. The weakest point of the rifle as I see it is the trigger, with is creepy and heavier than I would have expected. The trigger group is completely modular, however, and I would expect to see aftermarket replacement triggers appear on the secondary market before too long.
The barrel can be removed easily with a hex wrench, and DeserTech is producing a 5.56mm conversion kit. This will involve replacing the bolt, barrel, and ejection panel and installing a magazine well insert for the smaller magazine (the 5.56mm version will use AR pattern standard mags). The upper and lower receiver assemblies are completely interchangeable between calibers. For those wishing to use a suppressor, the gas system is adjustable, with 3 positions including one for suppressed use.
The rifle ships with a micro red dot optic mounted in lieu of iron sights. It is mounted to a single unit section of Picatinny rail integral to the gas block, meaning that it will retain zero when the barrel is removed. For those preferring other sights, the top of the receiver has a length of rail for attaching whatever you like. The handguard also has a top rail, but I would not consider it to be solidly fixed enough to retain zero on an optic. The handguard also has side and bottom MLok slots for bipods and other accessories. The handguard is not connected to the barrel, so bipods on it are effectively free floated.