New York City suffers hundreds of gun-related deaths each year, but some weapon manufacturers are bent on boosting the toll in 2006. And if the last week is any indication, the city’s murder enthusiasts had a lot to be thankful for. Using Queens as a representative borough: An 11-year-old girl was killed by a stray bullet Monday afternoon while cooling-off in a fire hydrant, and three men were found in possession of “cop-killer” handguns that are specially engineered to penetrate the protective body armor of police officers. This type of activity, while all-too-routine, is exactly what Mayor Bloomberg pledged to squash (along with and last vestige of NRA backing) with his much-heralded, bipartisan gun-control legislation last May. In it, he publicly indicted 15 out-of-state “rogue gun dealers,” whose deadly products regularly turn up on New York streets. One such dealer, Adventure Outdoors Inc. of Smyrna, Ga., has taken the Mayor to task and countersued for $400 million, charging slander to his “legitimate, lawful, family-run business.” The company, to whom at least 21 guns used in New York City crimes have been traced, bemoaned the legislation, citing the always-popular Second Amendment. While the lives of our friends and neighbors are doubtlessly valuable, you have to sympathize with our nation’s beleaguered artillery merchants. These days, it’s getting harder and harder to make an honest buck selling killing machines.