There are a seemingly endless number of makers turning out AR-15 rifle and carbine variants. Many of them offer a quality product, and a few don’t. It’s our goal to sort the two out. Now and then, however, a manufacturer goes beyond quality and incorporates innovation into their AR-platform weapon. The Marck 15 is one such gun. It represents the biggest design advance in the history of the AR, and is intriguing by its own merit.

Founded in 2005, MG Industries, of Bangor, Maine, has pushed the envelope in terms of the platform’s versatility by making it an individual, modular unit. The Marck 15, also known as the Hydra, was designed as a modular rifle capable of firing more than 16 various calibers, including .22, .223 or 5.56, 6.5 Grendel, 6.8 SPC, .450 Thumper, .458 SOCOM, 7.62×39mm, as well as the .45 Hybrid, M3 (Grease Gun) and LE in .45, 9mm and .40 LE (using Glock magazines), 7.62×25mm and the .45 Super Mag (.460), and .50 Beowulf. Many others are part of the MGI stable, with many more yet to go into production, but that’s another story. The weapon will be available in semi-auto (full-auto for military use).

While the ability to switch between calibers may seem like a complicated process, the average shooter can do it in around 90 seconds with MGI’s Marck 15, and all of its controls retain the familiar A2 configuration.

Modular Design That in itself is very useful, but it’s been done before with various uppers. What may pique your interest, however, is that the Hydra is capable of shifting to another caliber in roughly 20 seconds, without tools, and without changing the upper. To be realistic, the average person will probably make the transition in 90 seconds, likely faster with a bit of practice. The Hydra takes it a step further, though. It’s one thing for a weapon to do so with expensive proprietary components, but the Hydra does it all with standard barrels and magazines.

MGI’s Marck 15 Hydra can be configured to accept AK mags, which should come in handy for soldiers abroad who have captured enemy AKs. The Hydra’s adaptability even gives police officers an edge when they need to switch to .308.