Not to start a debate but it seems your definition of what a "Barrel
Bomb" is differs considerably from what the common definition is.
The MOAB recently used is far from being a "Barrel bomb".

Here's Wiki's definition of a barrel bomb:

"A barrel bomb is an improvised unguided bomb, sometimes described as a
flying IED (improvised explosive device). They are typically made from a
large barrel-shaped metal container that has been filled with high
explosives, possibly shrapnel, oil or chemicals as well, and then
dropped from a helicopter or airplane.[1] Due to the large amount of
explosives (up 1,000 kilograms (2,200 lb)), their poor accuracy and
indiscriminate use in populated civilian areas (including refugee
camps), the resulting detonations have been devastating.[2][3][4]
Critics have characterised them as weapons of terror and illegal under
international conventions".

I don't know why you think the MOAB use is a "barrel bomb".