Lt. Gov. Kathleen Kennedy Townsend, who coordinates the Glendening administration's crime policy, noted violent crime has declined in the state by 14 percent over the last two years.
"The gun law has contributed to part of that," she said.
Critics contend the law has done little more than inconvenience responsible hunters and sports enthusiasts.
"The government puts a law in place with the stated purpose of reducing crime. The only thing it does is make it more cumbersome for the law-abiding citizen," said Steve Palmer, who owns Appalachian Mountain Products in Keedysville.
"It's an affront to your Second Amendment rights," he said.
Palmer said the one-gun-per-month restriction has hurt his business. Although he relies primarily on his work as a gunsmith, he estimated the law has cut his handgun sales almost in half.
The law allows exceptions for collectors who are specially licensed with the state. A collector must send a notarized letter to the state police Licensing Division requesting the status, and a background check is conducted.
Pete Piringer, a state police spokesman, said about 500 Maryland residents have obtained the collector designation. Sgt. Frank Smith of the state police Licensing Division said few who have applied have been rejected.
Palmer said that is evidence the measure is ineffective.
"The one-a-month law is easy to circumvent," he said. "I know of no one who's been turned down."
While the decline of handgun sales is easy to chart, its impact on crime is much harder to assess.
The Hagerstown Police Department seized 11 handguns last year, up from eight in 1996, according to figures provided by the department.
But Chief Dale J. Jones said too many factors figure into such trends to draw any conclusions from the one-gun-per-month law.
"There are so many weapons on the street, both legally and illegally," he said.
Rohrersville resident Jim Warner, who has obtained the collector designation, said the law is little more than a nuisance to him. He ridiculed the idea that it has had any impact on crime.
Declining incidents of violent crime in Maryland mirror national statistics, he said.
"The purpose of this law is to make people hate gun owners," said Warner, who owns a variety of firearms for hunting, target shooting and collecting.
Warner, 57, also disputed whether the law is the reason gun sales have dropped. He said many people rushed to buy guns in 1994 before restrictions imposed by the federal Brady Law took effect.
Also, a declining crime rate has made people feel safer, and therefore less likely to buy guns for protection, he said.
"A lot of people have bought all the guns they can handle right now," Warner said.
Supporters said the law has helped in other ways. Townsend said the Washington, D.C., police have recovered fewer guns originating in Maryland since the law took effect.
Although she acknowledged that many factors determine crime rates, she said violent crime is dropping faster in Maryland than the national average.
"I don't think it's a serious imposition. To be very blunt, if my child can be saved, it's an imposition I am willing to accept," she said.