The phrase "match the powder barrel" is often used as an idiom to describe a situation or action that could lead to explosive consequences. There are several synonyms that can be used to convey a similar meaning, such as "light the fuse," "ignite the bomb," "set off a chain reaction," "spark a fire," "stoke the flames," or "fuel the fire." These phrases all suggest that a seemingly small action could lead to dangerous and unpredictable results. It is important to be cautious and thoughtful in our actions, as they may have unforeseen consequences that could ignite a chain of events that are difficult to control and contain.