HSM Standard Features When it comes to rifle ammunition HSM is always the right choice. Name any type of rifle shooting and HSM has a cartridge to fully handle the conditions and situation. And no HSM has never sat on its laurels. HSM Standard Specifications Brand: HSM Model: Standard Category: Centerfire Rifle Rounds Caliber: 300 Blackout Rounds Per Box: 20 Casing Material: Brass Game Type: Big Game Application: Hunting Bullet Type: Soft Point Boat-Tail (SPBT) Bullet Weight: 150 gr