Steelhooves takes 2 missiles and several mines.

The pseudo-goddess merely lowered her head, a spark of light bursting from her horn. In an instant, the two rockets had reversed course. The Steel Ranger tried to step back, but there was no time. The rockets impacted directly into our armored would-be savior, the explosion tossing the massive body back down the hill. The grass erupted in smoke and dirt and flame as the tumbling body bounced over several mines before coming to a stop, motionless and seemingly lifeless at the foot of the shack below.

Fallout Equestria: Chapter 14