Sadlak NM spring guides are hardened to the original USGI spec. 40 - 44Rc. In addition, each of our NM spring guides is hand inspected for straightness within .002 max. over the length of the guide. The result of this attention to detail is a spring guide which weighs 64 grams (2.3 oz), has the straightness to properly align the spring without binding, and the hardness to stand up to extended use without appreciable wear.
