SALEM – A felon, facing a 15-year mandatory prison term after being caught with a loaded gun in a car in Saugus last year remains free on $2,500, after pleading innocent.Ronald E. Burnett, 42, of 13 Monmouth St., East Boston, pleaded not guilty Wednesday in Salem Superior Court to charges of carrying a firearm without a license, carrying a loaded firearm without a license, possession of ammunition and being a felon in possession of a firearm after three prior convictions.Judge David A. Lowy set the same bail as previously set during a bail review, despite a strong plea from the commonwealth that it be increased to $10,000.In his pitch to increase the bail, Assistant District Attorney Michael J. Sheehan pointed out to Lowy that, if convicted, Burnett is facing a 15-year mandatory sentence, having been previously convicted in Suffolk County of drug possession in 2001, robbery in 1990 and assault and battery with a dangerous weapon in 1988.In the early morning hours of Nov. 9, Burnett was arrested after being stopped in Saugus on Route 1 in a vehicle that was pulled over by state police because of a motor infraction.Under the passenger seat where Burnett was seated, police apparently found a semi-automatic .40 caliber handgun.Defense lawyer Lawrence J. McGuire argued to Lowy that the bail should stay as it was set, noting that there have been no changed circumstances since his bail review, and the judge agreed.Burnett is due back in court on March 12 for a pretrial conference.