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Total Barrel Dynamics

The concept of Total Barrel Dynamics covers every aspect of the barrel that contributes to overall shotgun performance. This may include improvements to some or all of these key barrel features on most 12 and 20 gauge models. It is important to note that not all Browning shotguns have Total Barrel Dynamics and that some have only portions of the package of features. 

  • Chamber
  • Forcing Cone Design (Vector Pro, on selected models)
  • Barrel Steel and Manufacturing Process
  • Barrel Contour
  • Bore Diameter (Back Boring)
  • Choke Tube System Design (For example Invector Plus and Invector DS)
  • Choke Tube Constriction and Scaling

There are generally three aspects to Total Barrel Dynamics.

Importantly, Total Barrel Dynamics is limited to Browning's highest performance shotguns. Some other shotguns have some aspects of the concept, but only a few special shotguns have all. Namely 12 and 20 ga. Citori 725 shotguns, A5  and Maxus shotguns. BT-99 trap guns. Note that no 10 ga., 16 ga., 28 ga. and 410 bore shotguns utilize the system. Nor does any versions of the Browning Silver.

1. Vector Pro

Longer is better. The advantages of a lengthened forcing cone.

  • The forcing cone is the tapered transition between the chamber and the bore that constricts the shot column. The longer the forcing cone is, the more gradual the constriction.
  • A gradual constriction reduces stress on the shot column as it passes into the bore, resulting in fewer deformed pellets. Less pellet deformation produces more uniform patterns and keeps more pellets in the central part of the pattern. Vector Pro is better than the competitors’ forcing cone designs because of the more gradual constriction.
  • Lengthening forcing cones is a popular and expensive aftermarket practice done to increase shot pattern performance. But it comes standard on A5, Maxus, BT-99 and on 12 and 20 gauge Citori and Cynergy models. (Not found on the Browning Silver.)

2. Back-bored Technology

What is back-boring?

  • Back-boring enlarges the bore to the maximum diameter to increase shot velocity, minimize pellet deformity for more uniform patterns and reduce felt recoil.
  • Extensive testing has shown that Back-Bored Technology reduces the friction between the shot cup and the bore, but does not allow gases to slip past the shot cup that would result in reduced pellet velocity and blown patterns.
  • Back-Bore Technology specifications minimize shot deformation and maximize pattern uniformity, consistency and density. Back-Bored Technology is standard on A5, Maxus, BT-99 and on 12 and 20 gauge Citori, Cynergy, BPS and Silver models.

3. Invector-DS or Invector Plus

Taking choke tubes to the max.

  • Invector-DS choke tubes combine muzzle-end threads and thin-wall construction for a longer, more gradually tapered choke tube that produces extremely consistent, dense shot patterns.
  • From Cylinder to Extra Full, Invector-DS shot patterns tighten consistently in reliable, evenly scaled steps. • Muzzle threads minimize the flare at the end of the barrel for improved shotgun appearance. A slightly lighter overall barrel weight is achieved for faster swinging and improved balance.
  • The more gradual taper of Invector-DS choke tubes reduces shot deformation for fewer flyers and gaps in the pattern and allows higher shot velocities for hard hitting performance.
  •  The “DS” stands for double-seal. Our proprietary differential-banded brass seal compresses against the barrel wall to keep the choke tube threads clean and make installation and removal easier than any other muzzle thread system.
  • Invector-DS is standard on A5 and Citori 725 models in 12 and 20 gauge ONLY.

This video covers Total Barrel Dynamics as found on the Browning A5 shotgun.




A key is back boring. Back-boring increases bore diameter specifications and decreases friction between the shot cup and the bore to maximize shot pellet velocity and to reduce felt recoil. Also, reducing constriction from the forcing cone of the choke on the shot column results in fewer deformed pellets for more uniform patterns, and keeps more pellets in the central part of the pattern where they're needed to bag more upland birds, waterfowl and clay targets. Our back-bore specifications represent the ideal bore dimensions. A larger bore diameter can let gases slip by the shot cup, resulting in both reduced pellet velocity and blown patterns. A smaller bore diameter means the forcing cone can deform pellets, leading to flyers and poor ballistic performance.

Browning also optimizes forcing cone length and design where the shot leaves the chamber and makes its first constriction into the barrel itself. With Vector Pro (on some models with Total Barrel Dynamics) our lengthened cone reduced potential damage to shot in the transition for better pattern performance.

The strength of the Browning barrel is legendary, and built to handle the long-term punishment of steel shot.  Unlike some manufacturers' barrels whose guns face an uncertain performance lifespan after shooting steel, we have long been at the forefront of dependable steel shot performance and durability.

Our barrels meet the strictest material and construction quality standards. The barrel blanks are made from rolled and tempered steel bars and are stress relieved to maintain optimal mechanical properties. The barrel blanks are then precision drilled, reamed and honed to exacting specifications. Browning barrels will last and last.


  • Total Barrel Dynamics, including Vector Pro, is found primarily on select, back-bored 12 and 20 gauge models.
  • Any shotguns with the characteristics below DO NOT have the full Total Barrel Dynamics package of features as listed.
    • No small gauges (specifically 28 ga. and .410 bore)
    • No 10 gauge Browning shotguns
    • No 16 gauge Browning shotguns
    • No Browning Silver Model Shotguns 
    • No Browning shotguns with Standard Invector choke tubes
    • With multi-gauge sets, 28 ga. and .410 bore barrel sets will NOT have Total Barrel Dynamics, Vector Pro or back boring. 

The Tech-Term "Total Barrel Dynamics" is referred to in the following products:

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