This guide explains the purpose and application of witness marks on firearms. Witness marks, typically made with oil-based paint markers, are used to quickly verify if critical fasteners or sight adjustments have loosened or shifted. Applying a line across a fastener and its mating surface, or across an adjustable sight knob and its body, allows for an immediate visual check. If the lines are misaligned, it indicates a potential issue requiring re-tightening or re-zeroing. The process includes removing old marks with alcohol before re-applying new ones after adjustments.
You've reached the end! 1 videos loaded.
Gun Laws by State
Read firearms regulations for all 50 states + D.C.
Find Gun Dealers
Search licensed FFL dealers near you.
