Speer Deepcurl™ 38/357 Cal (revolver) - 357 Mag HP Bullet. Speer Bullets electro-chemically bonds the jacket to the core to create a tough bullet for the harshest of conditions. These DeepCurl bullets give reliable performance every time. Preformed petals give you controlled expansion. And, get the retained weight for deep penetration and excellent accuracy you need when it matters most.