Incorrect Unit for US Barrel in USCustomary.java?

[TywinLannister1313]

I am really new to Units of Measure so I apologize if I am missing something but I think USCustomary.java (link) has an incorrect value for BARREL:

public static final Unit<Volume> BARREL = addUnit(LITER.multiply(238.4810d), "Barrel", "bbl");

There are many different types of Barrel's but I don't know of any that are 238 liters. The class gives two references for where it gets its values:

United States customary units
Imperial and US customary measurement systems

I can't find any reference to a 238 liter barrel.

[TywinLannister1313]

I'm wrong. There is a "barrel" that is 238 liters called a "Hogshead".