Springfield (AP) – Gov. J.B. Pritzker authorized state regulation of firearms dealers Thursday in a reversal of his predecessor’s policy and prompting a gun owners group to threaten legal action against Illinois. Pritzker, sworn in on Monday, chose an elementary school in Chicago to sign legislation meant to cut down on illegal purchases of firearms through video monitoring, tighter inventory control and gun-shop employee training. The law affects about 2,400 firearms dealers and its provisions take effect in six months. Each must show it is licensed with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives and purchase a five-year state permit — $1,500 for retail shops and $300 for independent dealers. Each must install videotaping in retail sections of the store, maintain an electronic inventory and require annual employee training in spotting so-called straw purchases. The Illinois State Rifle Association promised a lawsuit challenging the plan.