The Full Metal Jacket Knuckle Bullet is a type of round that the lead core bullet is encased in a harder metal jacket on the front and sides? I didnít but I do now and with the Full Metal Jacket Knuckle Bullet Knife you will be a force to be reckoned with as it features its own full metal jacket. Built with a solid construction out of zinc aluminum this knuckle can throw down some harsh blows all the while protecting the userís hands. The palm bracer is designed to mimic a rifle cartridge while being able to brace for impact. Stylish and effective if you ask me. But this puppy has a secret. Yes, a secret. Hidden in the cartridge is a drop point knife. How cool is that? Just to seal this deal there is also a pin included to turn it into a belt buckle and transport your knuck with ease.