Zero a rifle and confirm the data

Confirm the system and authority. Follow the firearm, optic, mount, ammunition, range, and governing safety instructions. Inspect known critical fasteners and establish the intended rifle configuration. Use a measured target distance. Set the zero at a distance you can establish confidently and record whether it is yards or meters. Adjust from a repeatable group. Use group center and a stable position rather than chasing individual impacts. Let barrel, ammunition, shooter, and environmental variation remain visible. Record the reference. Preserve zero distance, angular units, sight geometry when used by the solver, ammunition lot, conditions, date, and any deliberate offset. Confirm after adjustment. Fire a fresh confirmation group after the final change. Re-check the optic's mechanical state and record the result. Validate beyond zero. Build or update the profile, recalculate, and compare multiple known distances. A confirmed zero anchors the trajectory but does not validate velocity, drag, atmosphere, or target data by itself.

Do not hide instability in software. If the zero will not repeat, stop and resolve ammunition, shooter, optic, mount, rifle, target, or range uncertainty before adding offsets or truing the ballistic model.