True Vertical

I dropped from the cast-iron valve wheel onto the foundation stones below. A discarded steel hex nut lay half-buried in the damp mulch. Scope cant needed checking after days of climbing. I plucked a loose, four-inch strand of jute twine from my sleeve fray and looped it tight through the center bore of the nut. Wedging the dry fiber into a hairline mortar fracture, I released the weight. The nut swung through three shallow arcs before settling dead still against the red brick. I brought the rifle stock to my shoulder and aligned the vertical reticle hair flush with the hanging strand. Zero degrees true. Baseline verified.