The SI Pistol Flat Wire Spring is an economical, easy do-it-yourself upgrade to any AR system with a Pistol Length Buffer System. The Flat Wire Spring design packs more energy than traditional round wire springs, giving it increased bolt power. Known for efficiency since the Flat Wire Spring is able to store a larger amount of energy in a smaller space. Having a larger surface area, the Flat Wire Spring distributes impact more evenly and reduces wear and tear outlasting the stock spring. Flat WIre Spring design also has less compressing force which increases reliability in cycling and is more resistant to friction and buckling.