Check the listing for details. GarandGear™ M1 Garand operting rod spring. Condition: New. Listed at 7.50 USD. We are pleased to be able to offer for sale a newly manufactured USGI spec operating rod spring. Our springs are manufactured in the USA using 17-7 stainless steel wire (ASTM A313) on state of the art CNC spring winding machines. After being formed our springs then undergo a heat treatment process which sets the springs to condition CH-900. This extra step (that many manufacturers skip) increases the ultimate tensile strength of the spring by over 21%. The heat treatment process also increases the yield strength of the spring by over 37%. USGI Specifications Q: What does USGI Spec mean? A: The army set forth certain parameters that an operating rod spring must meet. This specification is defined in drawing #6147568. These specification include things like wire diameter, outside diameter, maximum solid height, etc. The two most important parameters have to do with the spring rate. When the spring is loaded with a certain fixed weight (force) the spring must compress a certain distance. The specification states that when an operating rod spring is compressed with a 5lb weight the spring must compress to a length of between ( 16.75" and 17.75" ). When an operating rod spring is compressed with a 16lb weight the spring must compress to a length of between ( 11.75" and 12.75" ) Our M1 Garand operating rod spring has the following parameters: A 5lb weight compresses our spring to 17.1" A 16lb weight compresses our spring to 12.2" *** Lifetime Warranty on all our springs.. *** If you ever wear out or break one of our springs, just contact us and we'll send you a new one.