At the same time, the Department of Homeland Security has said it wants to buy more than 1.6 billion rounds of ammunition in the next four or five years -- which could put further strain on the supply.
The shortage, coupled with an increase in prices, comes as many gun owners head to the stores in anticipation of new gun control laws. States like Colorado and New York have already approved such legislation, while Democrats move toward bringing a bill to the Senate floor. At the moment, the congressional bill does not include an assault-weapons ban, but a ban is expected to be floated as an amendment.
Still, what one official described as "panic-buying" set in, as lawmakers rallied to draft new legislation in the wake of a series of tragic mass shootings last year, from Aurora, Colo., to Oak Creek, Wis., to Newtown, Conn.
In Tennessee's Hamilton County, the sheriff's department says its officers will be given fewer bullets when they train at the range.