HSM Ammunition Game King .300 Remington Ultra Magnum 165 Grain Spitzer Boat Tail 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 Remington Ultra Magnum 165 Grain Spitzer Boat Tail Brass Cased Rifle Ammunition: Manufacturer: HSM Ammunition Caliber: .300 Remington Ultra Magnum Number of Rounds: 20 Bullet Type: Spitzer Boat Tail (SBT) Bullet Weight: 165 grain Cartridge Case Material: Brass Application: Hunting Primer Style: Centerfire What is HSM Ammunition Game King .300 Remington Ultra Magnum 165 Grain Spitzer Boat Tail Brass Cased Rifle Ammunition good for? The manufacturer says that it is suitable for hunting.HSM Ammunition 300RUM12N: Game King .300 Remington Ultra Magnum 165 Grain Brass Cased Rifle Ammo 20 Rounds