Actually, steel barrels are still widely used today for transporting oil, petroleum products, and petrochemicals. In the US, these are traditionally 55-gallon or 208-liter barrels; in the UK and its former colonies, 44 imperial gallon or 200-liter barrels are used. The 200-liter barrel has de facto become the basic unit for transporting and selling oil and petroleum products when tankers, tank cars, or pipelines are not involved. The barrel itself has transformed from a physical unit into a measure of reserves, production, or supply, retaining its meaning exclusively in the oil industry, while in other contexts, barrels refer to completely different volume measures, still fractions of the largest wine barrel called a "tun," which equals 954 liters. To Russian ears, "barrel" may have become familiar, although people far from the industry still think it's 200 liters, but for foreigners, our "tonnes" also seem strange, not to mention Japan with its kiloliters.