"A bullet leaves the barrel of a Smith & Wesson M&P 15 traveling at 3,000 feet per second, covering the space of a large room seven times faster than a human can react. Five spiraling grooves inside the rifle’s barrel spin the bullet clockwise to improve accuracy. And, when the bullet strikes a person, it causes what Colorado Bureau of Investigation agent Dale Higashi on Wednesday called a “snowstorm effect,” breaking into hundreds of little flakes. “The damage it causes to the target, the damage it causes to the bullet itself, is dramatic,” Higashi said. On Tuesday and Wednesday, testimony in Arapahoe County District Court told the microscopic story of the Aurora movie theater shooting. Three evidence analysts described in tedious detail their scientific analysis of bullet fragments, pieces of metal and gunshot-residue swabs. On Wednesday, Higashi testified that, out of the 150 bullets, shell casings and fragments he looked at, all of the items he could trace linked back to one of three guns — including the Smith & Wesson rifle — investigators say James Holmes used inside the theater in July 2012."