Choreographer Roger Riggle and the student dancers in the "Montgomery College Summer Dinner Theatre Arts production of "The Unsinkable Molly Brown" in Rockville could give famous choreographers Agnes de Mille or Jerome Robbins and professional dancers in New York some sleepless nights. There's competition from a new quarter.

Their well-rehearsed execution of trick ensemble detail -- jumping on tables, cartwheels, tap routines, pulling along others in chairs and very physically shifting dance times -- approached professional precision. Only some of the exchanges of plain dialogue intruded on the impact of the show.

The 19-piece orchestra, which was seated back of the stage and led by Don Miller, played Meredith Willson's catchy music with a fine flair. Although the lead singers were well amplified and sang with sharp diction, their still-immature voices lacked a certain sparkle. Director Gerald Muller's good staging in the 21 scenes on three-level sets worked well. Indicative of the company's total involvement in all aspects of the dinner theater concept, Muller was seen carving the roast beef off stage for the dinner theater's sumptuous buffet. The college's 310-seat Fine Arts Theatre was sold out for this production and its second, Lerner and Loewe's "Camelot."