What is disruptive mass and how is it calculated?

[Exanthos]

I went against a ship that was barely larger than mine, yet it gave me a factor 14 mass disruption when I tried to jump away. Even when I got away from the ship, my charging meter barely moved before I was destroyed. When I try and stay near small enemies, they never seem to be effected by a mass disruption, and can warp away right in front of me >:(

[BlueLightning]

This called mass lock, read this for more explanation
https://elite-dangerous.fandom.com/wiki/Mass_Lock#:~:text=%E2%80%8BMass%20Locked,%22High-Waking%22).

[Agony_Aunt]

Every ship has its own MLF, which does not correlate with its own mass, but there is a general trend the bigger the ship the higher MFL it has.

The wierd ones being the Python (which has a higher MLF than one might expect) and the Type 9 (which has a much lower MLF than one would expect).

Look at a site like coriolis.io, it lists the MLF for each ship in one of the columns.