Promag Industries uses a proprietary DuPont Zytel polymer to injection mold magazine bodies and followers. The precision wound springs are manufactured from heat-treated chrome silicon wire. These features ensure a long service life of unparalleled reliability and feeding. The 22 Long Rifle magazine designed for the Smith & Wesson M&P 15-22 will provide hours of plinking fun. The loading button on the side of the magazine allows the user to compress the spring and eliminate sore thumbs from a long day at the range.