Product of the US-based company Desert Tech LLC MDR rifle is a modular, multi-caliber weapon with compact bullpup layout. It is built around the powerful 7.62x51 NATO (.308 Win) ammunition, and can be easily adapted to a number of smaller and less powerful rounds with replacement of the barrel and bolt head, and installation of the magazine well adapter. Barrel lengths and calibers can be changed by the end user within minutes with minimum amount of tools.