The green spring is a versatile and reliable component designed for optimal performance in A1/A2 fixed stock rifle length receiver extensions (buffer tubes) paired with rifle length buffers. Its robust design mirrors the load specifications of a brand new mil-spec buffer spring, ensuring consistent and dependable operation. Primarily engineered for use with smaller calibers such as .223 Cal, 5.56x45mm, 6.8 SPC, 6.5 Grendel and 7.62x39mm, the Green spring excels in A2 rifle length tubes. However, its adaptability extends to long barrel (20 inches+) rifle length gas systems in heavier calibers like .308 Cal, 6.5 Creedmoor and .260 Remington. In these scenarios, pairing the Green spring with an H2 or H3 carbine buffer has proven effective, providing a balanced and smooth cycling experience. For firearms experiencing over-gassing issues, particularly in heavier caliber configurations with rifle length tubes, consider our Red or Orange carbine springs. These, combined with standard length 3.25 inches carbine buffers and a spacer, can adjust the tube depth to accommodate longer bolt carrier groups, ensuring optimal performance and reliability. Whether you're fine-tuning a precision build or seeking to enhance the reliability of your rifle, the Green spring offers a robust solution for a wide range of applications, delivering the performance and durability you expect from a high-quality buffer spring. The green spring is compatible with A1/A2 fixed stock rifles and VLTOR A5 buffer tubes and is optimized for .223 Cal, 5.56x45mm and similar calibers It can also be utilized for larger calibers in long-barrel rifles; however, it may necessitate the use of an H2 or H3 buffer for calibers such as .308 For rifles with longer barrels that are over-gassed and use heavier calibers, it is recommended to use red or orange carbine springs in conjunction with a standard carbine buffer and spacer