Winchester Supreme 270 WSM (Winchester Short Mag) 150gr Ballistic Silvertip Rifle Ammo - 20 Rounds - Due to recommendations of outdoor writers, guides, outfitters, and consumers, Winchester is adding heavier weight Supreme Ballistic Silvertip bullets to some of the most popular hunting calibers. Polymer Tip; Alloyed Lead Core; Contoured Jacket; Rapid Controlled Expansion;