The teens, identified as Brandon Michael Shreve, 18, of Linthicum, Md., a 16-year-old from Glen Burnie, Md., and a 15-year-old from Baltimore, were pulled over at about 1:40 a.m. Sunday after a police officer observed them driving in a suspicious manner, The Washington Post reported.
During a search of the vehicle, officers said they found the ammunition, as well as bolt cutters, flashlights and latex gloves.
Authorities said they believe the teens were involved in a break-in at a trailer owned by the federal air marshal program.
All three were taken into custody.
2014: The Year in Music [PHOTOS]