https://matteocampagna.com/en/registry/equipment/arrow-buckling-power-stroke Changes to this claim in Matteo Campagna's evidence registry: its status, its year-by-year history, revisions of the page. en-gb https://matteocampagna.com/en/registry/equipment/arrow-buckling-power-strokeThe models have agreed since 1997 that the string's thrust compresses the arrow and makes it flex more; none of the available calculations has it pushing the arrow past the instability threshold. The model that put figures on the phenomenon places the loss of stability at a dimensionless force of 14.79 and the peak thrust of an average target bow and arrow at 12.3: above the threshold of the static column test, 9.87, but below the one that applies in the shot. The only estimate on real equipment, a compound with a spine 500 arrow, gives a peak axial load of about 60 newtons against a critical load of about 100, a little over half the threshold. A second model by the same author writes in its conclusions that the launch is characterised by instability, but the arrow it uses for verification sits at 5.28, well short of the threshold of 15. The aluminium kyudo shafts tested on the bench give way at 50 and 65 newtons, far below the force of their bows, through instability rather than because the material is overloaded, but in the case where the point slips behind the bow and the arrow is trapped, not in a normal launch. The evidence therefore goes against the claim, but it is scant and indirect: an estimate on a single bow, with the models pointing the same way without measuring anything. The margin shrinks with more draw weight, more point weight, and longer or weaker shafts, and nobody has instrumented an arrow during a shot close to the limit.claim:freccia-instabilita-carico:revision:2026-10-12:4Mon, 12 Oct 2026 08:00:00 GMT https://matteocampagna.com/en/registry/equipment/arrow-buckling-power-strokeclaim:freccia-instabilita-carico:new_claim:2026-10-01:contraddettoThu, 01 Oct 2026 08:00:00 GMT