30 gallons seems to be standard for short fat barrels.
Bill D.
No idea if the links below will hold up to vacuum pressure. But free shipping!
https://www.amazon.com/Eagle-1654-Bl...0662341&sr=8-5
https://www.amazon.com/Eagle-1601MB-Polyethylene-Lever-lock-Capacity/dp/B0025QI4XC/ref=sr_1_5?dchild=1&keywords=30+Gallon+Drum&qid=16 00662541&sr=8-5
check the reviews for the above . some are using them for dust collectors