There is a strong body of evidence that validates the advantages of using an extended choke over the flush choke that comes from the gun manufacturer. The flush choke is commonly referred to as a “conical” design and the extended choke is of the “conical/parallel” design. In the case of the flush choke, the conical section eases the transition of the shot/wad from the bore of the shotgun through a tapering cone to the final constriction. The conical/parallel sections of the extended chokes not only eases the transition from bore size to the final constriction, but also gives the shot/wad a "moment" of stability before exiting the choke.

What are the advantages/disadvantages of a flush choke? Let’s take a look:

  1. The flush choke tapers down to the final measured constriction at the very end of the choke/muzzle of the gun. The shot/wad exits the choke with no dwell time for the shot to conform or “settle in” to the final constriction.
  2. The combustion gases pushing the shot/wad column out of the choke creates turbulence at the end of the muzzle as the gases abruptly expand. This can cause turbulence on the shot/wad as they leave the choke which creates “fliers” of some of the individual pellets.
  3. I really don’t see any advantage to the flush choke in my opinion! They are relatively low cost and the gun manufacturers have to supply something to protect the choke threads of the barrel.

Extended chokes have been with us almost as long as flush chokes. They incorporate a “conical” section that gradually tapers down to a separate “parallel” section. This is a section of the choke of some length that extends beyond the muzzle of the shotgun. In this case, the parallel section is the constriction of the choke itself. One can find extended chokes supplied by the shotgun manufacturers and the aftermarket. The lengths of the extensions can be as small as one half inch to as much as two inches.

What are the advantages/disadvantages of the extended choke? Let’s take a look:

  1. In the extended choke, the conical section gradually tapers the shot/wad to the parallel section keeping pellet deformation to a minimum. But, once the parallel section is reached, the shot/wad then has some amount of dwell time for the shot to redistribute in the choke before exiting. This again minimizes the possibility of pellet damage.
  2. This slight redistribution of the pellets into a more conformal but stable mass of shot in the shot/wad column, in essence, “tightens” up the pellets which  results in “tighter” patterns. Many times a shooter can come back a constriction as most shotgunners tend to choke too much! The only way to find out is to pattern with the shotshell load you intend to use.
  3. There is less turbulence at the end of the parallel section. It would be like spraying water through a pipe attached to the end of your garden hose, i.e., a straight stream!
  4. The extension itself also enables the manufacturer to more easily “mark” the choke with the constriction. This is a definite plus for the shooter looking to replace the choke with another constriction in a hurry.
  5. The extension acts as a handy way of tightening the choke after a shooting session without the need for getting out the choke wrench.

If you are looking for an extended choke, BlackBore chokes are the ones to consider. They also have some distinct advantages to the shooter that others do not offer!