https://www.vice.com/en_us/article/z34x3e/heres-what-we-know-about-the-homemade-gun-that-killed-shinzo-abe

Shinzo Abe, the former Prime Minister of Japan, was assassinated with a gun on the streets of Nara, Japan. The killing shocked the world and, especially, Japan—a country with strict gun laws and tight control over ammunition. It appears that the killer used a homemade gun to carry out the attack. 

Officials in Japan, journalists, and firearms experts have all called the gun used to kill Abe “homemade.” Typically this refers to a 3D printed weapon, but the weapon used to kill the former Prime Minister appears more crude than that.