Sierra Bullets .25 Caliber 70 Grain BlitzKing FB Rifle Bullets. The tips of these bullets are made of a proprietary compound and the jackets are thin for enhanced accuracy and explosive expansion. The lighter bullets in 20 & 22 calibers are designed to be fired at muzzle velocities up to 4400 fps. The lightest 6mm BlitzKing bullet can be fired at muzzle velocities up to 4000 fps. The 25 caliber 70 (flat base) & 90 (boat tail) grain BlitzKing bullets were created to fill the demand for the longer range varmint crowd taking over where Sierra's current .20-6mm BlitzKings leave off. Ballistic Coefficients and Velocity Ranges .260 at 3150 fps and above .251 between 2800 and 3150 fps .242 between 1800 and 2800 fps .230 at 1800 fps and below Specifications for Sierra Bullets .25 Caliber 70 Grain BlitzKing FB Rifle Bullets: Manufacturer: Sierra Bullets Bullet Type: Flat Base Spitzer Bullet Weight: 70 grain Projectile Caliber: .25 Caliber Diameter: 0.257 in G1 Ballistic Coefficient: 0.26 G7 Ballistic Coefficient: 0.23 Sectional Density: 0.151 Bullet Quantity: 500 Bullet Country of Origin: USA Package Contents: Sierra Bullets Rifle Bullet .257 Diameter 70 Grain BlitzKing Green-Tipped 1605CS 500 Count The Sierra Rifle Bullet .257 Diameter 70 Grain BlitzKing Green-Tipped 1605CS is a quality addition to the Sierra Bullets lineup. For more great deals on Rifle Bullets by Sierra Bullets please browse our Sierra Bullets Reloading Equipment page. Sierra Bullets Rifle Bullet .257 Diameter 70 Grain BlitzKing Green-Tipped