Dealing and Wheeling in Small Arms opens with a cheerful Cambodian shooting off rounds, without earphones, in a shady gallery. This is what he does to unwind on weekends, he explains (what he does on weekdays is tactfully unexplored). If nothing else in Sander Francken’s conscientious documentary on illicit arms trading packs the same kick (there’s something powerful in outrageous behavior presented without editorial), it’s still worthy without turning outright dull. Francken explores different angles via a number of guides—Congo’s Raphael Katabarwa, massacre survivor and witness, and British journalist Christian Jennings are the most featured—but he’s basically telling two unequal stories. Jennings does international investigative reporting of the kind no U.S. paper or TV station seems willing to pay for anymore, sifting through stacks of customs reports for arms that should land in America but make “fueling stops” in Third World countries. As far as the other strand: Anyone who needs to see former child soldiers crying to understand that civil wars do bad things to children needs to read more (though a scene of ex-soldiers in camp playing war with sticks—complete with executions—has an eerie charge to it). Francken ends with hands thrown up at the U.N.’s inefficacy; his documentary makes a big show of only scratching the problem’s surface, but suggests that even that is more than that body has done.