Charles Krupa, Associated Press
A box of AR-15 rifle lower receivers awaiting serial number stamping and finishing at the Stag Arms company in New Britain, Conn., Wednesday, April 10, 2013.

HARTFORD, Conn. — Federal authorities are seeking to keep a third of the nearly 300 assault rifle parts they seized from a Connecticut gun maker that prosecutors allege broke federal firearm regulations.

Prosecutors asked a federal judge in Bridgeport earlier this month to allow the U.S. government to retain the AR-15 parts confiscated last September from Stag Arms in New Britain.

Agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives say they found about 3,000 AR-15 parts without required serial numbers and a lack of required records at the company. Officials seized some of the parts.

Court documents say the father of Stag Arms' owner told authorities the employee who puts serial numbers on parts was on vacation.

Stag Arms officials say changes have been made to ensure compliance with the law.