The Apocalyptica
A new model is not required, but if you're a nice human you are welcome to create a new from scratch

The weapon itself, should be a one-shot mechanism. No big flashy gattlin' gun or such, exactly like original Bertha. Although the reload time should be enourmous, and im talking about a 20 - 30 min reload time.
And now all you balance freaks go nutz. The fired shell should have the power equivalent of 10 commanders exploding on same time. In other words, a explosion 10 times the size of one comm death. Thats the reason for the name.
Other than that, the range should be unlimited. For other reasons, a more rapid fire version should be made too.
Thats it. If its a bad reply, then dont reply at all, thx!
(If this aint allowed here, please remove it)