Sen. Kirsten Gillibrand introduced a bill Wednesday that would raise the age to buy military assault weapons from 18 to 21. The same age requirement already applies to purchasing handguns from federally licensed dealers.

People under the age of 21 have used military-style semi-automatics in some of the most devastating shootings in U.S. history, Gillibrand said. That includes the 2022 mass shooting at a Tops Supermarket in Buffalo.

More than 85% of deaths in public mass shootings involving four or more fatalities were caused by a weapon like these, according to Gillibrand’s office.