The forensic scientist for the Bridgeport, Conn. Police Department sharply criticized proposed assault weapon and high-capacity magazine bans and pointed out the small number of crimes committed by high-capacity weapons in public hearing testimony last week. Marshall K. Robinson, who said his area of expertise is “firearm and tool mark identification,” testified at the Gun Violence Prevention Working Group, which was convened at the Connecticut State Capitol in response to the Sandy Hook Elementary School shooting. There he opposed statements from many of the other 1,300 speakers in attendance advocating for banning high-capacity AR-15 and AK-47 firearms. Robinson pointed out...