The Franklin County district attorney's office dropped a uniform firearms act violation charge against Frazier because of insufficient evidence, said T.R. Williams, assistant district attorney.
The felony can carry a maximum of seven years in prison.
Frazier told police the pistol belonged to him, according to charging documents. The pistol had the serial numbers removed from its frame, the documents said.
Police said Frazier purchased the gun on a downtown Chambersburg street.
The Accelerated Rehabilitative Disposition program is a probational program for first offenders, Williams said.
The program requires Frazier to pay administrative fees, court costs and other expenses, and abide by the rules while under probationary supervision, he said. If the probation period is violated, Frazier would face the drug charges again, Williams said.
Frazier was not charged with shooting Casanova. Franklin County District Attorney Jack Nelson ruled that the shooting, though unintentional, was justifiable.
Shortly after 3 a.m. on April 23, Casanova, who was armed with a sawed-off baseball bat, and two other masked individuals, one armed with a 12-gauge shotgun, entered the back door of the residence at 4496 Sycamore Grove Road.
Casanova was shot when Frazier's firearm discharged after briefly scuffling with Casanova.
The Fraziers have since moved from that address.
The others, including three alleged lookouts and another in a getaway car, fled the scene. Pennsylvania State Police arrested six suspects less than a week later, charging them with burglary, attempted robbery, attempted theft and criminal conspiracy.
The group planned in advance to break into the Frazier residence with the intent of robbing the family of money, valuables and drugs, according to court documents.