This is a Winchester Ammunition Polymer Tip known as the Deer Season XP chambered in 450 Bushmaster, model X450DS.
Deer Season XP ammunition combines Winchester's extensive experience into a product engineered specifically for deer hunters. The Extreme Point bullet features an oversized impact diameter. A bigger impact diameter means more impact trauma" better energy transfer and faster knockdown.
Features:
450 Bushmaster
2,200 Feet per second
250 Grain extreme point
20 Rounds per box