Angron tanks Shadowswords firing anti titan guns at him

"A pair of colossal Shadowsword super-heavy tanks rolled up behind the main column and pivoted their Titan-killing main guns towards the flame-wreathed primarch.
Kossolax held his breath.
He felt his hearts stop.
Raging against his foes' impotence, Angron burst through the wall of ordnance and the Shadowsword's siege-breaking beams and stamped down on the glacis plate of the lead tank."

-Angron: The Red Angel