The Department of Homeland Security is under investigation for purchasing large stockpiles of ammunition, days before legislation was introduced that would restrict the amount a government agency can legally buy.

The Government Accountability Office is now conducting the investigation into the alleged DHS purchases, which is “just getting underway,” GAO spokesman Chuck Young told US News & World Report.

DHS officials have repeatedly denied stockpiling ammunition, but AP reports claim that the agency plans to buy more than 1.6 billion rounds of ammunition over the next four or five years, and has already bought 360,000 rounds of hollow point bullets and 1.5 billion rounds in 2012.

DHS claims that it is buying ammo in bulk to save money, but experts have pointed out that hollow point bullets cost nearly twice as much as full metal jacket rounds. They also explode on impact for maximum damage, which has caused some Americans to wonder what purpose they would serve the DHS domestically. Purchasing 1.6 billion rounds of ammo would also give DHS the means to fight the equivalent of a 24-year Iraq War. Members of Congress say the DHS has repeatedly refused to tell them the purpose of procuring such large amounts of ammo.

“They have no answer for that question,” Congressman Timothy Huelscamp told Infowars in March, pointing out that the purchases are being made at a time when sequestration should be limiting the agency’s spending. “…We’re going to find out… I say we don’t fund them until we get an answer.”

DHS officials testified last week that it was only planning to purchase up to 750 million rounds of ammunition for training centers and law enforcement over the next five years. The agency's spokesman, Peter Boogaard, told Congress that the media reports are ‘misleading’. But Boogard also mentioned a second five-year contract for up to 450 million rounds of ammunition for law enforcement purposes. Together, the two DHS contracts for ammunition would result in purchases of up to 1.2 billion rounds of ammo.

“With more than 100,000 armed law enforcement personnel in DHS, significant quantities of ammunition are used to support law enforcement operations, quarterly qualifications, and training, to include advanced firearms training exercises,” Boogard said.

But the DHS testimony did not provide an adequate explanation for the large amount of ammo it plans to procure, prompting a GAO investigation at approximately the same time as the introduction of the AMMO Act.

The new legislation, which was introduced in both the Senate and the House on Friday, would prevent government agencies from buying any more ammunition if its stockpiles are already larger than what they were in previous presidential administrations.

Proponents of the bill suspect that government agencies may be making large ammunition purchases to keep the supplies out of the hands of Americans at a time when the administration has been trying to reduce gun violence.

“President Obama has been adamant about curbing law-abiding Americans’ access and opportunities to exercise their Second Amendment rights,” US Sen. Jim Inhofe, who introduced the bill, said in a news release. “One way the Obama Administration is able to do this is by limiting what’s available in the market with federal agencies purchasing unnecessary stockpiles of ammunition… [DHS] has two years worth of ammo on hand and allots nearly 1,000 more rounds of ammunition for DHS officers than is used on average by our Army officers.”

Congressman Frank Lucas cited an ammunition shortage in Oklahoma and blamed the DHS for taking away Americans’ Second Amendment rights by removing ammo from the market.

The GAO investigation will attempt to determine whether there truly is a reason for the large ammo purchases, or whether DHS is simply buying large quantities to save money in the long run.