100x Premium Quality Rubber Steel Balls in 50 caliber for Paintball and Self Defense Guns. Manufacturer's ,Certificate of Approval: Balls are made of %50 Rubber and %50 Steel Powder. Article Details: 100 Hard Mix Rubber - Steel Balls suitable for 50 caliber paintball and RAM weapons. The rubber-steel ball ammo is also ideal for slingshots. They are made of very strong rubber and mixed with steel powder. Due to the very high quality, the rubber steel balls are super precise and also significantly rounder than comparable balls. One box of Rubber-Steel Balls (100 pieces) in 50 cal. weighs 295 gr. (one single piece weighs around 2,7 gr.) Very good shot and hit picture for paintball pistols in 50 caliber. This projectile, weighs heavier than the standard rubber balls, will be dispatched at very high speed. They are perfect for home and self defense.