From vuurwapenblog.com via thefirearmblog.com: “As you can see, the carbine buffer allowed the bolt carrier to bounce back after making contact with the receiver extension. Many people say that this isn’t a problem unless the weapon is firing full auto. While malfunctions are not as common on semi auto, is this really something you want your weapon doing? Even the heavier 9mm buffer allowed a similar amount of ‘bounce’ – it doesn’t have the heavy internal weights of the carbine or H buffers. The BCM H buffer, though, with its heavier (and separate) internal weights, practically eliminated the issue.”
