Vertical position indicator for optical sights

An optical sight for firearms, wherein the improvement comprises a roll-axis vertical position indicator, said indicator comprising a non-buoyant spheroid free to seek under the force of gravity a true vertical position;

• said indicator contained within a housing comprising a transparent, tubular toroid mounted coaxially and posterior of the ocular lens of the optical sight;
• said indicator free to move by rolling within said housing without the impediment of pivots, mechanical linkages, or any attached structure whatsoever.