Better known under his pseudonym JStark1809, Jacob Duygu (born in 1992 or 1993, died in July 2021) was a German-Kurdish gun designer. With contributions from the "guerrilla 3D-gun file development group" Deterrence Dispensed, JStark designed and manufactured the original FGC-9, a physible, 3D-printable semiautomatic pistol caliber carbine.