Of course, the Glock 17, which is made in Austria, is not porcelain. While the frame is made of polymer, 83 percent of the gun by weight is made of ordnance steel. The entirety of the gun are visible in x-ray machines. Nobody has ever made a porcelain, ceramic, or entirely plastic firearm that can't be detected by security screening devices. Even if there were such a gun, the ammo inside is still brass and lead.