 Some turkey hunting tubes have constrictions greater than "Turkey", or additional features like porting to reduce recoil, or "straight rifling" that is designed to stop any spin that the shot column might acquire when traveling down the barrel.These tubes are often extended tubes, meaning they project beyond the end of the bore, giving more room for things like a longer conical section.Shot spreaders or diffusion chokes work opposite of normal chokes—they are designed to spread the shot more than a cylinder bore, generating wider patterns for very short range use.