Federal authorities expressed confidence Thursday that the dozens of guns thathave not left the area.
"We've been in contact with Interpol, and we've made them aware," said Agent Wade Rasberry of the Bureau of Alcohol, Tobacco, Firearms and Explosives. "There isn't an active (international) investigation because there is nothing to say that the guns are outside the border."
Rasberry said the disappearance has no known connection to terrorism.
Four men were arrested in connection with the disappearance, including Cameron Johnson, a contract security guard who was on duty at the shipping company's facility in Shreveport, La., the day the guns were supposed to arrive.
The other three men arrested have a long history of charges, including drug possession, theft and possession of firearms, according to the Caddo Parish Sheriff's Office, which is also investigating the disappearance.
The suspects are due to appear in court Nov. 21.
The weapons, AR-15 Cold Law Enforcement Carbines, left Colt Manufacturing in Hartford, Conn., on a truck headed south. Once the guns were scanned in Shreveport, employees at the transport company, Con-way Inc., noticed a pallet of 63 weapons was missing.
The guns were headed for Sports South, which boasts being "the country's oldest and largest single-source distributor of firearms and ammunition."
None of the guns have been recovered. Law enforcement agencies have the serial numbers of all missing weapons, which could be used to track guns that turn up on the market or in criminal incidents.
Officials from Con-way declined to comment and deferred questions to the sheriff's office.
"The company continues to fully cooperate with the Caddo Parish Sheriff's Office on its investigation," the sheriff's office said in a statement on its website.
Colt Manufacturing has also been unavailable to comment.
The sheriff's office said the investigation was ongoing and that some buyers may have purchased weapons unaware that they were stolen.
"Anyone recently acquiring this type of weapon from anyone other than an authorized or legitimate dealer is encouraged to contact the sheriff's office," the sheriff's office said.
According to an ATF survey, more than 190,000 firearms were lost or stolen in the United States in 2012.