MTU is quite the beefed up barrel. Possibly close to a pound heavier than M40 profile.
Don’t know how much more it’s needed.
I guess the fatter it is the stiffer it is, when stiff reduces barrel whip, which then does ???? (I’ll google it to see actual effects of barre whip)
I like it because it heats up a lot slower then a light barrel. After 10 rounds in 2 minutes, the MTU is considerably cooler then my old medium palma.