JE Machine Tech AR-15 Buffer Spring Black. 56x45mm NATO .223 Remington Features of JE Machine Tech AR-15 Buffer Spring: 1 3/8 inches Package Contents: JE Machine Tech AR-15 Buffer Spring The J & E Machine Tech Je Ar15 Buffer Spring is a quality addition to the JE Machine Tech lineup. For more great deals on AR15 Buffer Springs by JE Machine Tech please browse our J & E Machine Tech Gun Parts page. What firearm models does the manufacturer say JE Machine Tech AR-15 Buffer Spring is compatible with? The manufacturer suggests that JE Machine Tech AR-15 Buffer Spring is compatible with AR-15JE Machine Tech JE Ar15 Buffer Spring