A group called Conflict Armament Research released a report today on the origin of ISIS ammunition which was researched by cataloging seized caches and spent shells from militant positions. Nearly 20 percent of the 1,700-some cartridges the group studied came from the United States; other sources included China, Russia, and the Sudan. Some were almost 70 years old. From the report:

CAR documented ammunition manufactured in 21 countries, with dates of production ranging from 1945 to 2014. Two production periods, the 1970s–80s and the 2000s, are most represented in the sample and primarily consist of ammunition manufactured in China, Serbia, Soviet Union/Russian Federation, and the US.

It’s not surprising that ISIS is using American ammo, as the group is known to have seized weapons that were given to the Iraqi military by the U.S. But as America begins arming yet another group of Middle Eastern militants (Syrian rebels, to be specific), it’s a reminder of how quickly the work of the Lake City Army Ammunition Plant in Missouri—to take one example from the report—can end up in the hands of hostile forces.