Our Standard Head Assembly is designed to be used exclusively with our Pivot Stand base. The AR500 plate is mounted flush against the 2x4 post so the energy from the bullet is transferred into the post. The Pivot Stand is designed to allow the 2x4 post to move when struck. We do not recommend mounting this head to a rigid 2x4 post. If you plan to use a rigid mounted 2x4 in your application, please consider shopping in our Reflex Head category.