It may have only been breakfast in Bethesda, but for Tony Fisher, who had been stalking the sheriff for months, it was like a shootout in the Old West at high noon.

Fisher, a 12-year veteran in the county police department with a hankering to be sheriff, has been appearing at political forums across Montgomery County since he began his campaign six months ago. But a recent early-morning gathering at the Hot Shoppes on Wisconsin Avenue at East-West Highway was the first time the man he has been gunning for, Sheriff Jim Young, showed up.

When they finally stood face to face, Young, 58, a law man for 20 years, stood on one side of the room, casually puffing a cigarette and gazing confidently into the distance. Fisher, who wore a crisp business suit for the showdown, unleashed a fierce barrage of campaign charges.

"Most of the citizens of this county consider the sheriff's office an innocuous office in county government because the head of that office has not proved otherwise," said Fisher, taking aim as Young's only challenger in the Sept. 14 Democratic primary. "I will make the office of county sheriff something you can be proud of."

Young, firing back with the confidence born of six years of wearing the sheriff's badge, answered that "the sheriff of Montgomery County should have first-hand knowledge of how the office operates. I've done a lot to bring the sheriff's department out of the dark ages and I have a lot more innovative ideas," he told members of the Bethesda-Chevy Chase Breakfast Club.

Fisher, 32, a county police detective with a B.A. in business from the University of Maryland who is chairman of the 20,000-member National Black Police Association, said he would bring "fresh ideas and professionalism" to the job. If successful, he would become the first black elected to a partisan, county-wide office in Montgomery.

In the opening shots of his campaign last March, Fisher charged Young with "mismanagement and waste" in the administration of the 66-deputy department.

Fisher estimated the county had lost some $30,000 in interest income because Young had failed to promptly transfer to the county treasury about $208,000 in various fees collected over a five-month period from late 1981 until last April.

Young acknowledged that regular transfers of the funds had not been made, but he denied that it was because of mismanagement. It was the result of manpower problems, the sheriff said, and he promised to correct the problem.

Fisher's charges sparked a County Council request for an audit of Young's financial records. The audit substantiated the transfer problems and led to new procedures for handling the money collected by the sheriff.

Fisher also charged that the office of sheriff has been passed down over the past 30 years "like a family heirloom," filled primarily through internal appointments rather than by elections.

He said the big problem with bringing the sheriff into office through appointments, as Young was six years ago, is that there is no guarantee of getting the best person for the job.

Fisher has raised about $10,000, and has appeared at almost every political forum he could, firing off charges at his missing adversary.

Young, who was elected four years ago, has done little more than put his name on literature distributed by "Democrats for 82," the slate of party incumbents.

But when he stood up to Fisher recently, he fired off several rounds of what he described as his "outstanding record of performance." While a deputy, Young said he lobbied successfully for a bill that placed the sheriff's department under the merit system for county employes, a move that he said resulted in higher pay and job security for the deputies and a greater degree of professionalism. As chief deputy, Young said he convinced the 23 county sheriffs in Maryland to help him support a bill that placed sheriff's departments across the state under the Maryland State Police Training Commission, which trains all other major law enforcement officers in the state. And Young said his office wrote a courtroom security training manual that is used to train sheriff's deputies in counties across the state.