I just recently came across a steel oil barrel in excellent shape with the two heavy ribs around it. Embossed lettering on top with company and date of 1914. When did they generally change from wooden barrels to steel?

Sam are you sure it is a date? All of Pierces had a tracking number that was on barrel no two the same and was on receipt in a effort to get them returned. I have both steel and wood but can't help you with dates. I have a steel with the mail out card asking for its return with matching numbers. Pretty cool I think.