The .308 buffer spring is an important link in the overall function of your AR system. A properly weighted and installed buffer spring can make a difference of several hundred rounds in some cases, completely overwhelming your stock spring. Over a thousand rounds can create a buffer spring fatigue situation. While an over-recoil spring may seem like a good idea initially, the longer the buffer tube the more likely it is to break or wear. While a 'light' buffer spring may initially seem like a good idea, a 'heavier' spring may be the better choice in some instances. The 'lighter' spring allows the shooter to use less ammunition. The buffer spring does, however, need to be replaced after only a few shots in order for the shooter to become fatigued and require less shooting. It is, however, still a good idea to keep a buffer along with your standard spring until you find that the spring is adequate for your needs.