BA Tube Artillery, stats are in Tactical Operations, is the best representation of a real world heavy mortar (120 mm range with auto loader) in BT, in my opinion. BA tube artillery has the range, it's an area effect weapon and it's relatively light at 500 kg, less ammo.
It also ranks high on my list of cheap, low tech, no-brainer weapons for BT that should have been in the game from the beginning, like rocket launchers. But I digress.
I have scaled up as a heavy weapon to mount on vehicles to provide artillery support for infantry. Most BA scale weapons scale up to heavy class with a multiplier of around 3 or 4.
So what do you think a scaled up to heavy weapons class, BA tube artillery should weight?
I think 2.0 tons but I'd like input from others.