The guns are then taken to urban areas to be sold, Plantz said.
If a customer passes the background check under the federal Brady Act, there is no limit to the number of guns he can buy, police said.
Police recounted one example when 30 guns were bought during a single purchase in the Charleston area.
"It's an overwhelming problem," Plantz said during the Statewide Violent Crime Reduction and Crime Gun Interdiction symposium at the National Conservation Training Center.
Plantz said the legislature needs to pass tougher laws to correct the situation, but that he doesn't hold out much hope.
Jefferson County Sheriff William Senseney said any effort to curtail gun purchases would be met with strong opposition by the National Rifle Association.
Local lawmakers could not be reached for comment Tuesday.
Plantz was speaking from a statewide perspective, but police said the problem is probably having an impact locally.
"I think it's happening all over," said Capt. Larry Bradley, who oversees the state police detachments in Berkeley, Jefferson and Morgan Counties.
In Maryland, a person can buy only one gun every 30 days, said Sgt. Denton Lowry of the Hagerstown state police detachment. Exceptions can be made for law enforcement and correctional officers, Lowry said.
Virginia has a similar law, according to Bradley and Senseney.
State police from West Virginia, Maryland, Pennsylvania and Virginia, as well as officials from such other agencies as the federal Bureau of Alcohol, Tobacco and Firearms, met to trade ideas on how to reduce gun violence.
In Virginia, officials say they have been able to reduce violent crime through a number of new programs, including "Project Exile," in which gun violators are prosecuted through federal courts where sentences are tougher.
Officials had been particularly concerned about crime in Richmond, where criminals were "killing people left and right," said Capt. Larry Burchett of the Virginia State Police.