Underwood Subsonic Rifle Ammunition 8.6 Blackout Features The Subsonic Rifle Ammunition is loaded with a 300-grain Custom Competition hollow point boat tail projectile a bullet design that combines the accuracy-optimizing aerodynamics of the boat tail base geometry with the terminal performance characteristics of a hollow point cavity in a high-weight subsonic configuration purpose-built for the 8.6 Blackout cartridge. The copper and lead construction delivers the consistent dimensional uniformity and ballistic coefficient performance needed for precision target applications and the heavy 300-grain weight is specifically optimized for the subsonic velocity envelope of the 8.6 Blackout platform. At 950 fps from a 12-inch test barrel this load remains reliably subsonic across a wide range of barrel lengths ensuring consistent suppressed performance without the sonic crack associated with supersonic ammunition. The nickel-plated brass case provides a corrosion-resistant smooth-cycling case surface that feeds reliably in semi-automatic and bolt action 8.6 Blackout hosts while offering excellent case life for reloaders who want to recycle premium brass after initial firing. Suppressor-safe certification ensures this load is engineered to function reliably without the excessive carbon debris or pressure issues that can affect suppressor performance and longevity with non-approved loads. The 601.6 ft. lbs. of muzzle energy delivered by the 300-grain projectile at subsonic velocity provides meaningful terminal performance for target applications while remaining within the subsonic performance envelope that defines the 8.6 Blackout platform s primary use case. Underwood Subsonic Rifle Ammunition 8.6 Blackout Specifications Manufacturer: Underwood Model: Subsonic Rifle Ammunition Cartridge: 8.6 Blackout Bullet Weight: 300 gr. Bullet Type: HPBT Bullet Construction: Hollow Point Boat Tail Bullet Material: Copper Lead Bullet Model: Custom Competition Muzzle Velocity: 950 fps Muzzle Energy: 601.6 ft. lbs. Test Barrel Length: 12 Case Type: Nickel Plated Brass Velocity Rating: Subsonic Suppressor Safe: Yes Lead Free: No Gun Type: Rifle Rounds Per Box: 20