Updated

A maker of military-style rifles pleaded guilty Tuesday to violating federal firearms laws, and the owner has agreed to sell the company.

Sloppy record-keeping and a failure to comply with regulations at Stag Arms of New Britain left the company unable to account for hundreds of weapons, prosecutors said.

"It is critically important for those who are responsible for manufacturing firearms, especially high-powered semiautomatic rifles, to diligently comply with federal firearms laws throughout the production and distribution process," said Deirdre Daly, the U.S. attorney for Connecticut.

In Hartford federal court, Stag Arms' owner, Mark Malkowski, entered a guilty plea on the company's behalf to a felony charge of possession of a machine gun not registered to the company. The company agreed to pay a $500,000 fine and to not challenge the revocation of its license in court, prosecutors said.

In New Haven federal court Wednesday, Malkowski is expected to plead guilty himself to a misdemeanor charge of failure to maintain proper firearm records.

The company has been licensed since 2003 and manufactures semi-automatic rifles.

In a prepared statement, Stag Arms said it believes public safety was never compromised, but the company and Malkowski agreed to enter guilty pleas because it is in the best interests of the company and its employees.

Inspections last year by agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives found dozens of unregistered machine guns or machine gun parts. Investigators said more than 3,000 guns were transferred by the company without being property recorded.