Inventor of World’s Most Popular Assault Rifle Felt Responsible for Millions of Gun Deaths

Mikhail Kalashnikov spent much of his life defending his most famous invention, the AK-47 assault rifle. But a newly released letter suggests the creator of the world’s most popular firearm felt some qualms later in life about the millions of deaths caused by his invention.

Russian newspaper Izvestia released the letter Monday, which Kalashnikov wrote a few months before his death in December to Russia’s Patriarch. “My spiritual pain is unbearable. I keep asking the same insoluble question. If my rifle deprived people of life then can it be that I…a Christian and an orthodox believer, was to blame for their deaths?” he asked.

Kalashnikov designed the AK-47 for the Soviet Union’s Red Army in 1947, and the semi-automatic rifle was quickly characterized as a favorite among soldiers, guerilla fighters, and terrorists. In the U.S., at least three recent mass shootings were carried out with AK-47s.

Though he usually defended his invention — Kalashnikov called his invention “a miracle weapon” in his last letter — it seems that later in life Kalashnikov became more conflicted. “I’m proud of my invention, but I’m sad that it is used by terrorists,” he said in 2002. “I would prefer to have invented a machine that people could use and that would help farmers with their work – for example a lawnmower.”