BALTIMORE -- Maryland State Police will be trading in their revolvers for 9 mm semiautomatic pistols.

The switch is part of a nationwide trend by police agencies away from revolvers. A 9 mm pistol has greater firepower and accuracy than a .357 Magnum, the weapon now used by state police, and is easier to reload, said Carl Banaszewski, director of planning and research for the state police.

Banaszewski said last week that state police will probably put the weapons purchase out to bid this month.

A decision to make the switch in Maryland was made after a review of "what's going on nationwide with other police agencies," and local tests of the 9 mm pistol, Banaszewski said.

State police in Connecticut and New Jersey are among some of the other law enforcement agencies that have turned to 9 mm pistols.

Maryland State Police expect various manufacturers to submit bids, Banaszewski said, adding that officials have not specified a model preference.

State police are requiring the manufacturers to offer minimum 15-round weapons.

Maryland troopers are currently armed with Smith & Wesson .357 Magnum frame revolvers that fire .38 specials. They must be reloaded after firing six shots. One of the advantages of the 9 mm weapon is that the bullets are contained in a clip, which Banaszewski said makes it easier to reload, "particularly at night or in adverse conditions."

State police have spent the last year studying whether to make the switch.

The state will need to purchase at least one pistol for each of the approximately 1,600 state police personnel who carry weapons, Banaszewski said. He said he was not able to estimate how much the weapons would cost.

Banaszewski said that barring any problems, he expects a contract to be awarded early in 1988.

While the state police seek bids on the new weapons, they will seek a buyer for their old revolvers, Banaszewski said.

All troopers will have to requalify on the new weapon before they can trade in their present handguns.