D.C. police arrested a Cheverly man yesterday and charged him with possession of a loaded, unlicensed .25-caliber pistol. The arrest occurred at a construction site at 1120 Vermont Ave. NW, which as been the scene of a labor dispute.

Police arrested Robert Majors, 49, as he finished his shift after receiving reports from other workers that he was carrying a gun.

Earlier, about 20 striking laborers cursed and threw stones at what they said was a nonunion concrete mixer, which succeeded in pouring a load of concrete and leaving the job site. Police were present to maintain order.

About 12 policemen subsequently fanned out around Thomas Circle and escorted dozens of workers away from the site.

According to the striking workers, yesterday's pouring was the first since the walkout of about 25 laborers and some ironworkers and sheetmetal workers on June 24.

The dispute began with an organizing election last May when the laborers voted in favor of a union. Laborers assit carpenters and other craftsmen in construction tasks.

The management, Leon N. Weiner Construction Associates, objected to what they said was inclusion of four operating engineers in the organizing vote and the election still has not been certified.