Sierra BlitzKing Rifle Bullets .22 Caliber Boat Tail BT 55 grain 500 Bullets/Box. The nose tips of the bullets are made of a proprietary acetyl resin compound and the sharp tips improve the ballistic coefficient over the traditional flat-base Spitzer bullet design. The 55 grain #1455 has a boat tail to further increase ballistic coefficient compared to a flat-base design in these bullet weights. All the BlitzKing bullets in 22 caliber are designed to be fired at muzzle velocities up to 4400 fps. Specifications for Sierra Bullets BlitzKing Rifle Bullets .22 Caliber 55 Grain BlitzKing: Manufacturer: Sierra Bullets Gun Type: Rifle Pistol Caliber: .22 Hornet Bullet Weight: 55 grain Projectile Caliber: .22 Caliber Diameter: 0.224 in Sectional Density: 0.157 Country of Origin: USA Features of Sierra Bullets BlitzKing Rifle Bullets .22 Caliber 55 Grain BlitzKing BlitzKing bullets are designed for explosive expansion in varmints and small game and with accuracy characteristic of the MatchKing 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. Package Contents: Sierra Bullets BlitzKing Rifle Bullets .22 Caliber 55 Grain BlitzKing Sierra 1455C: BlitzKing Rifle Bullets .22 Caliber Boat Tail BT 55 grain 500 Bullets/Box