Proof Research 22 Caliber Blanks patented manufacturing process begins with full-profile, match-grade 416R stainless steel barrel blanks that are made in their firearms division.  These blanks are then turned down to a significantly reduced profile greatly reducing weight. This reduced contour barrel is then wrapped with high-strength, aerospace-grade carbon fiber impregnated with a proprietary matrix resin developed by their advanced composites division, PROOF Research ACD. The aerospace-grade carbon fiber used has a specific strength up to 30 times that of stainless steel and a specific stiffness up to 7 times greater than steel. Strength and stiffness are only part of the equation. Heat conductivity and thermal expansion are also of paramount importance when developing a match-grade carbon fiber barrel. The helical wrapping pattern favors the longitudinal thermal diffusivity of the carbon fibers (along the length of the barrel) allowing them to more efficiently dissipate heat emanating from the barrel rather than insulating it. Because Proof Research rifle barrels are engineered for thermal performance, they also move heat very effectively through the wall (thickness) of the barrel, greatly increasing heat transport and resulting in barrels that cool faster and maintain accuracy over longer sessions of fire. The end result is an aerospace-grade, high-fiber content composite barrel that is stronger, lighter, as accurate as the finest precision steel barrel, and maintains its accuracy in the most demanding environments. THE ONLY CARBON FIBER-WRAPPED RIFLE BARREL APPROVED FOR USE BY THE U.S. MILITARY.