HSM Ammunition Game King .300 Remington Ultra Magnum 150 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 150 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: 150 grain Cartridge Case Material: Brass Muzzle Velocity: 3390 ft/s Application: Hunting Primer Style: Centerfire What is HSM Ammunition Game King .300 Remington Ultra Magnum 150 Grain Spitzer Boat Tail Brass Cased Rifle Ammunition good for? The manufacturer suggests that it is good for hunting.HSM Ammunition 300RUM11N: Game King .300 Remington Ultra Magnum 150 Grain Brass Cased Rifle Ammo 20 Rounds