When gunpowder was made in batches, you didn't know how powerful it was until tested. NRA Museums director Jim Supica shows John Popp eprouvettes, or powder testers. They load like a flintlock, but push a wheel when fired. How far it turns shows the power of the batch. Historians find them in many configurations, including ones fashioned from real flintlock pistols. Also resembling a pistol is the 19th century tinder light. The "barrel" holds the tinder and the mechanism creates the spark to ignite it. It also holds a candle which is lit and used in turn to light other candles.