Maxim Defense Industries SBA Short Barrel Ammunition 8.6 Blackout 235 Grain Match Grade Solid Copper TUI Tumble Upon Impact Design 20 Round Box. To address these concerns" Maxim Defense partnered with Fort Scott Munitions to optimize ammunition loads specifically for SBRs. By making these adjustments" as well as including their TUI (Tumble Upon Impact) technology" the Maxim Defense Ammunition ballistic wound cavities exceed the standards of both Expanding and Fragmenting projectiles. The TUI design of the projectiles tumble all the way down to 500 fps. Specifications for Maxim Defense Industries Short Barrel 7.62x39mm 117 grain Solid Copper Rifle Ammunition: Manufacturer: Maxim Defense Industries Additional Features: Copper Bullet Type: Solid Copper Lead Free: Yes Application: Hunting Home Defense Primer Style: Centerfire Cartridge Case Material: Brass Caliber: 7.62x39mm Number of Rounds: 20 Features of Maxim Defense Industries Short Barrel 7.62x39mm 117 grain Solid Copper Rifle Ammunition: Short Barrel Ammunition Package Contents: Maxim Defense Industries Short Barrel 7.62x39mm 117 grain Solid Copper Rifle Ammunition