Can you describe how you were holding the pump head and wheel? That's where I'm still drawing a blank.

For example, I hold the pump head in my left hand. The head is against my palm by the fourth and fifth fingers. My thumb is parallel to the valve stem, against the rim and tire. My index finger and middle finger wrap around the tire from the back side. Fourth and fifth finger wrap around the spoke next to the valve stem. Even using a Silca to hit 100psi with hypothermia in the rain there's no way the pump head can move enough against the stem to cause damage. Or at least it never has for me.