Sierra Bullets Sports Master 9mm Caliber 115 Grain JHP Rifle Bullets. The jackets are formed to specific velocities and pressures to produce optimum uniform expansion. Sierra has incorporated a patented process which during the manufacturing actually seats the bullets in the bore throats. The necks of these slugs are precision machined from solid copper bar stock. The tips are swaged flat and the hollow points are tapered. Upon impact the serrations within the hollow points expand and trap the gasses from the central vacuum. The result is greater energy retention and greater weight retention with less fragmentation risk. Sierra's mechanical design is also patented or approved by the SAAMI JSA. Specifications for Sierra Bullets Sports Master 9mm Caliber 115 Grain JHP Rifle Bullets: Manufacturer: Sierra Bullets Bullet Type: Hollow Point (HP) Jacketed Hollow Point (JHP) Bullet Weight: 115 grain Sectional Density: 0.13 Condition: New Projectile Caliber: .355 Caliber Bullet Quantity: 100 Bullet Country of Origin: USA Fabric/Material: Copper Package Contents: Sierra Bullets 8110 Sports Master 9mm .355 115 GR Jacketed Hollow Point (JHP) 100 Box Sierra Bullets 8110 Sports Master 9mm .355 115 GR Jacketed Hollow Point JHP 100 Box