This is a Sellier & Bellot Full Metal Jacket known as the Rifle chambered in 300 Blackout, model SB300BLKB.
Sellier & Bellot rifle ammunition is designed and field-tested to provide shooters and hunters with the widest selection of caliber offerings and the highest performance projectiles on the market today.
Features:
300 Blackout
2,076 Feet per second
147 Grain full metal jacket
20 Rounds per box