“ORANGE Spring” The ONLY specifically engineered EXTRA POWER Buffer Spring for .308 Carbine Platforms using standard 7″ Depth M4 extension tubes and .308 short 2.5″ buffers (Including aftermarket “heavy buffers.”) You cannot clip coils from any other commercially available buffer spring to yield the proper spring loads for this application, especially in heavily gassed .308 carbine platforms. We started from scratch on this design to provide Operators with a viable alternative to existing OEM and aftermarket offerings. Platforms known to exist using this approach include DPMS, Bushmaster (Post 2010), Remington, CMMG, Mega, SA Defense, Colt 901, Rock River Arms and many others. Color Coded ORANGE.