 Complete the following phrase:  The SKS is popular on the civilian surplus market, especially in Canada and the United States. Because of their historic and novel nature, Soviet and European SKS carbines are classified by the ATF as Curio  Relic items under U.S. law, allowing them to be sold with features that might otherwise be restricted. Chinese manufactured rifles, even the rare early Sino-Soviet examples, are not so classified, though the Sino-Soviet rifles qualify for automatic Curio  Relic status due to being manufactured over 50 years ago. Because of the massive size of the Chinese Peoples Liberation Army, over 8 million Chinese SKS rifles were manufactured during their 20 years of use making the Chinese SKS one of the most mass-produced military rifles of all time although still far behind its successor the AK-47. An SKS was reportedly one of the weapons used by the perpetrator of the 