The OTs-14 Groza (ОЦ-14 "Гроза") is a Russian selective fire bullpup assault rifle chambered for the 7.62×39 round and the 9×39mm subsonic round. It was developed in the 1990s at the TsKIB SOO (Central Design and Research Bureau of Sporting and Hunting Arms) in Tula, Russia. The weapon is colloquially known as OC-14 or OTs-14 "Groza" ("Thunderstorm"). The OTs-14-4A "Groza-4" has one derivative, the TKB-0239 (ТКБ-0239), also known as OTs-14-1A "Groza-1", chambered for the 7.62×39mm round.