This paper describes three unique metal matrix composite (MMC) material systems that have been developed for use in dimensionally stable platforms, precision mechanical systems, and lightweight reflective optics. These engineered materials, consisting of aluminum alloys reinforced with fine particles of silicon carbide, offer distinctive performance advantages over conventional metals, including greater specific stiffness, higher strength, and better resistance to compressive microcreep. Weighing about the same as aluminum, certain grades of these MMC materials are isotropic and have excellent thermal conductivity, and they can be tailored to match the coefficients of thermal expansion of other materials, including beryllium, stainless steel, and electroless nickel. Such flexibilities in establishing material properties and characteristics present new opportunities to the designer in producing weight-critical, precision hardware. Practical applications of MMC materials in advanced guidance equipment and lightweight optical assemblies are presented and discussed.