Subscribe | UPI Odd Newsletter Subscribe JIANGSHAN, China, Sept. 30 (UPI) -- A U.S. daredevil in a wingsuit said his "flying dagger" jump through a narrow mountain fissure in eastern China was his most "hardcore" stunt. Jeb Corliss, 37, a professional skydiver and BASE jumper from the United States, said he used smart glasses that rendered a three-dimensional rendering of the fissure in the Jianglang mountains in China's Zhejiang province for his training in Hungary prior to his Saturday stunt, NBC News reported Monday. Advertisement Corliss said his training was less successful than Saturday's jump through the fissure, which is only 60 feet wide at the top and 15 feet wide at the bottom. "I would say I impacted about 50 percent of the time," Corliss told Outside magazine of his training. Corliss said his jump from the helicopter Saturday topped all of his previous stunts. "I have never experienced anything so hardcore. Period. I have not been that scared in my life. It was so powerful and overwhelming. I started crying," he said.