Kinetic Research Group’s was for me one of the most interesting booths in the whole show. Justin, the CEO of KRG, is a delight to talk to for anyone interested in the details of small arms design. TFB’s Rusty S previously covered some of KRG’s other products, but left it to me to discuss one of their most interesting products: The FOX-42 semiautomatic precision rifle. KRG brought an early FOX-42 non-firing prototype to the SHOT Show last year to gauge interest, and apparently that paid off, since 2016 saw them bringing a fully-functional firing prototype, albeit still sporting some rapid prototyped components.

The FOX-42 is a fascinating rifle, using a lightweight bolt carrier with an even lighter 4-lug, short-throw rotary bolt. Justin had ready answers to the tough nitty gritty questions I like to ask, such as “what’s the mass ratio of the carrier to the bolt?” (about 5-to-1, he says), and I was downright impressed with his grasp of small arms design theory.

A look at the 4-lug bolt of the KRG FOX-42.

The gas system on the FOX-42 is a direct impingement type, flowing into a hollow extension in the bolt carrier shaped like a de Laval nozzle, which gives the gas the correct thrust for operating the mechanism. Gas vents just forward of the receiver, according to Justin, so the rifle runs cleaner than an AR-15 without the excess weight and complexity of a piston gun, and while still achieving the quasi-free-floating effect possible with DI rifles. This also allows the operating group to be as light as possible, a distinct advantage in a precision semiautomatic rifle where a heavy, bucking mechanism can disturb a rapid follow-up shot.

Justin hinted to TFB that KRG had several other ideas in the works, as well. For the FOX-42, like all of the company’s projects, Justin said “it will be done when it’s done”.