Police found the weapons cache, which included several machine guns, at the Montrose, California, home of 39-year-old Joshua Corbett following his June 8 arrest at Bullock's residence in an upscale neighborhood near Beverly Hills, prosecutors said.
Corbett, who has already pleaded not guilty in Los Angeles Superior Court to felony charges of burglary, stalking and possession of a machine gun, now faces 19 additional felony weapons charges.
Corbett's bail was set at $2 million on the new charges in addition to the $185,000 bond from the original charges. He is being held in Los Angeles County Jail.
Bullock, the star of such films as "The Blind Side" and this year's Academy Award-winner "Gravity," was at home during the alleged break-in but prosecutors said Corbett was not in possession of the machine gun at the time of the break-in.
A message left with Corbett's attorney, Stephen Sitkoff, was not immediately returned. Sitkoff has said that Corbett suffers from serious mental health issues and did not intend to harm Bullock.
Corbett faces up to seven years and four months in prison if convicted on the three earlier felony counts as well as an additional maximum prison term of 12 years for the new counts.