BlackBore Choke Articles


Thoughts Regarding Backbored Barrels

Written by BlackBore Mark.

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!

What's New In Hunting Shotgun Chokes

Written by BlackBore Mark.

After a seemingly endless summer, hunting season for most of us is finally here! Fall is in the air and its past time to break out the favorite shotgun to clean, check, and prepare the shotgun for the work ahead. Hopefully, the hunter will take the time to brush up on their shooting skills on the skeet and sporting clays field!

In most states, the start of the hunting season brings hunters out to harvest small game and birds such as dove, quail, pheasant, rabbit and the like. It is important that the shotgun hunter match his choice of shotgun shell to the game and to use the right choke to deliver the shot for that one shot kill. The shotshell manufacturers do a great job of providing the recommended load for the game, but it is not so easy to pick the shotgun choke that will give the hunter the highest probability of hits.

As the shotguns come from their respective factories, most chokes supplied are either of the conical flush-type (ends at the muzzle) or of the conical/parallel extended-type with the latter finding the most favor. While there are lots of opinions on what the length the parallel section should be, almost everyone will agree that a conical section (as determined by the manufacturer of the shotgun) with some amount of parallel section greatly helps in the transition of the shot through the choke. After all, the less stress on the shot the better so that they will fly as true as possible to the intended target.

There are many manufacturers of aftermarket shotgun chokes out there and they all make chokes suitable for the hunting fields. Usually, shotgun manufacturers such as Browning, Beretta, Benelli, Winchester, Mossberg and others have particular shotgun models just for field use, with camo finishes and extended chambers for the 2-3/4", 3" and 3-1/2" hunting loads. Pump and semi-auto actions are the most numerous. Any of these will do the job and choice usually boils down to personal preference.

There is a new manufacturer of hunting chokes for the field hunter. The BlackBore HunterPro series of chokes are manufactured with ports incorporating a cutting blade within the port itself. The BlackBore HunterPro Choke is designed to be used with a particular port blade width and number of ports for a particular shot size range. That's because field loads within a range of shot use different wads of different thicknesses and configuration. When the shotgun is fired, the wad with the shot passes through the choke where the port blades slice off "slivers" of the wad, slowing the wad and preventing the wad from interfering with the shot column as it leaves the muzzle. You will see the evidence of this in the surrounding air when you shoot and on the ground in front of the muzzle. Patterns should show improvement because "flyers" will be eliminated.

If the shooter is not happy with testing loads and field results, but sure to try various other shotshell loads. Once the right choke/shotshell combination for your shotgun is determined, the hunter can concentrate on bringing home the game!