BlackBore Shotgun Choke Articles


As one who owns many shotguns (hunting, competition, testing), I have some thoughts regarding backbored barrels. No great revelations here, but something to consider when reading about the pros and cons of backbored shotgun barrels.

Probably the most often stated advantage for backboring or purchasing a gun with a backbored barrel is that backbored barrels help give better patterns and reduces felt recoil. Let's look at some particulars.

SAAMI dimensions for 12 gauge shotgun barrels specifies .729" as Cylinder bore (manufacturing tolerances +- .002"). This has been the standard bore for many years and many thousands of guns are equipped with these barrels today. But what about factory shotguns that come with "backbored barrels"? Is there a "standard" dimension out there that all manufacturers comply with?

Unfortunately, there is no standard for backbored barrels and with little agreement as to what the bore dimension should be for backbored barrels. Bores range from .733" to .745" or more (the more metal you remove, the lighter the barrel, but also the thinner the walls). As a manufacturer of shotgun chokes and a believer in patterning your shotgun/choke/load combination, I have recovered hundreds of shell wads and recorded the measurements and condition of each one. These wads were recovered after firing through factory and aftermarket non-ported choke tubes, ported chokes and, of course, BlackBore chokes.

An unfired wad removed from a new shell of common, popular shotgun ammo measures about .715" at that point where the petals merge into the body of the wad and .695-.700 for the body itself. When a shotshell wad/shot column is fired in a .729" barrel, the expansion at the wad base is still about .695"-.700", the waist is running about .710" and at the junction where the petals meet the rest of the wad has expanded out to .729". This was especially obvious when shot from the barrel with the BlackBore choke where the blades in the ports mutilated the base, sides of the wad and the petals. It was not so obvious when examining the wad fired through non-ported choke tubes as there is little damage to the wad.

What happens in a backbored barrel? Using the same ammo and recovering the wads, the base and sides of the wads showed expansion to the backbored barrel inside diameter. The petals of the wads are deformed to a greater degree because of the greater amount of expansion. This could indicate a greater potential for pellet deformation (which doesn't help the flight of the pellet to the target).

What's the bottom line? All shotguns tested with backbored barrels gave good patterns using extended conical/parallel chokes.  A backbored barrel shotgun may not be the great advantage that so many think it might be! By letting more of the combustion gases escape around the wad/shot column during its journey up the barrel, there might be some lessening of felt recoil, but that is very subjective and hard to prove. I would say that a ported extended choke releasing gases near the muzzle of the barrel would help to reduce felt recoil more, but that is just an opinion. Is there a more likelihood of pellet deformation with a backbored barrel? There are indications that this might be happening, but it is probably not enough that the shooter would recognize the difference from one pattern to the next. Something to keep in mind!

Also, keep in mind that BlackBore Chokes help you shoot your best, no matter if you have a standard barrel or backbored barrel! By consistently slowing the wad at the moment the shot leaves the barrel/choke, the patterns from your shotgun will always be dense and evenly distributed because the wad will not "blow thru" the shot column as the shot exits the barrel!

Everyone is doing it (the manufacturers of shotguns, that is)! Tactical shotguns are mainstream now and just about every manufacturer offers a model or two. Remington, Mossberg, Benelli and FN just to name a few. The shooting community is made up of many civilian shooters, LEO's and members of the Military who purchase and use these types of shotguns.

Typically, they are 12 gauge and of the pump and semi-auto action persuasion with a dark or camo finish, magazines that hold multiple rounds and sights that enhance the probability of hitting the target (whatever that might be). Ammo is usually one of the buckshot and/or slug loads. They look and feel like the tools that they are and are capable of doing any job asked of them! But what of the shotgun's choke? What is its function and where does it fit in the great scheme of things?

Since a shotgun's primary job is to deliver multiple pellets in a dense, consistent pattern to the target or object, the shotgun depends on a constriction at the muzzle to keep the shot together to said target, depending on the distance. The shotgun's barrel may come from the factory with Cylinder bore (really not a "choke" at all, but the barrels inside diameter, usually .729") or with threads in the barrel so that a screw-in type choke can be changed to different constrictions.

Tactical chokes usually sport a black oxide finish or durable coating to eliminate any reflections. The latest fad is for the choke to sport "teeth" at the muzzle end as a standoff device. They may look  menacing, but are not too practical. To each his own.

BlackBore Tactical HD shotgun chokes are available for most of the tactical shotguns on the market today. What makes the BlackBore Tactical HD choke different? Each port incorporates a wide blade that cuts, slices and slows down the wad surrounding the shot or slug as they pass through the choke. This means that the wad will not interfere with the shot/slug at the moment it leaves the barrel. After the shot is taken, you will see slivers of wad in the air around you and on the ground in front of you. Check the pattern at the target. You will see that the pellets are more evenly distributed and concentrated and that is what the game is all about! For slugs, you should see the holes touching or very close together.

Consider BlackBore Tactical HD for your next tactical choke. If you don't see one for your shotgun, contact us and we will try to help you!