[Ross F-1]

Supposedly (from what I've read on the Garage Journal), true MAPP gas is no longer produced. What is sold now is a substitute that is not as hot, many dissatisfied users.

From Wiki: "In the spring of 2008, true MAPP gas production ended in North America when production was discontinued at the only remaining plant in North America that still manufactured it. Current products labeled "MAPP" are, in fact, MAPP substitutes. These versions are stabilized liquefied petroleum gas (LPG) with high levels of propylene."