HSM Ammunition Game King .300 AAC Blackout 125 Grain Spitzer Brass Cased Rifle Ammo 20 Rounds. Now HSM has developed an entire lineup of fine hunting ammunition featuring the time-honored Sierra GameKing/Pro-Hunter bullets. Each caliber's individual components have been precisely matched to each GameKing/Pro-Hunter bullet to maximize their potential for accuracy and performance. Specifications for HSM Ammunition Game King .300 AAC Blackout 125 Grain Spitzer Brass Cased Rifle Ammunition: Manufacturer: HSM Ammunition Caliber: .300 AAC Blackout Number of Rounds: 20 Bullet Type: Spitzer Bullet Weight: 125 grain Cartridge Case Material: Brass Muzzle Velocity: 2200 ft/s Application: Hunting Primer Style: Centerfire What is HSM Ammunition Game King .300 AAC Blackout 125 Grain Spitzer Brass Cased Rifle Ammunition good for? The manufacturer suggests that it is suitable for hunting.HSM Ammunition 300BLK3N: Game King .300 AAC Blackout 125 Grain Brass Cased Rifle Ammo 20 Rounds