American Precision Arms Generation 3 Fat Bastard was the result of the desire to meet the demands of the Long-Range and Hunting markets. APA has combined the standards of high-level performance and reliability with distinctive design enhancements to improve both accuracy and performance. These enhancements benefit the shooter experience at the range and in the field where every advantage matters. Among the design, changes are three key features. The advanced Unique Recoil Profile tunable top port design allows the shooter to fine-tune the muzzle movement for absolute target retention. In addition to that, the new lock nut design creates a zero over rotating platform. Last, is the addition of a fifth Bastard port section that eliminates even more recoil than before. *Note- Made for a barrel diameters of .850 or larger. Able to handle magnum cartridges. Includes set screws, Allen wrench and a single-use Threadtite.