Browning was an innovator of developing choke tube inserts to increase versatility of the shotgunner's barrels. Now he could easily change tubes without changing barrels. The Browning Invector Choke tube system was extremely innovative for hunters.
The Invector Choke Tube system utilized barrels with internal threads to screw in chokes of the shooter's choice. A wrench was supplied to facilitate removal and installation of tubes. Popular choke constrictions were offered, including Extra Full Turkey tubes and rifled chokes for deer hunting, using Sabot, slugs or heavy buckshot.
Shortly after the introduction of the Invector System, Browning introduced the Invector-Plus system. These new tubes were made to fit in back-bored barrels. For many years, trap shooters had been back-boring (over boring) their barrels to decrease recoil, allowing the shot to disperse more uniformly, therefore providing more consistent patterns. Browning offered many more choices in tubes such as longer tubes to change barrel balance, specialty tubes for deer and turkey, as well as sporting clays, trap and skeet. Shooters can take tubes in the field now and adapt quickly to changing shooting choke requirements. The line has expanded to over 35 different configurations of high quality steel tubes for your shotgun.
Both for steel and lead shot, these tubes are made for Browning barrels only and should not be used for other shotgun brands. Be certain to always check your barrel markings for proper gauge and choke, whether it is the Standard Invector or Invector-Plus system.