This is the mechanical stem that holds the target on the cheap auto resetting targets that they sell on amazon, It was a gift from my sons grandmother that another jerk kid my son invited over decided to destroy, remix as you like, drawn in solidworks as close to the original as i could get.

Printer:
Prusa MK3S+

Material:
ABS

Printed with .25 infill

Reference:
https://www.amazon.com/UWANTME-Electric-Scoring-Shooting-Digital/dp/B07H7HLVCG