Barrel is a measure for crude oil 42 US Gal. It can be a container for beer, wine and spirits.
Drums are the containers for the carriage of Avgas, Avtur, Petrol, Diesel, Lube Oil. A drum nominally contains 44 Imp Gal, 55 US Gal or 200 Litres.
I have never heard a 44 referred to as a "barrel"