If the nock is loose on the nocking point, the arrow changes its impact height
2 studies
The summary today
Nobody has measured it. The only work that mentions it is the commissioning of a Japanese shooting robot: with a practice bow of about 9 kilograms of draw force, at 18 metres, the same arrow, pulled from the target and shot again ten times, always stayed inside a 160 millimetre circle, but with a vertical spread that the robot alone does not explain. The authors put it down mainly to the nocking point, wider than the nock on a practice bow: the arrow sits in a slightly different place each time, changes its angle and therefore its height on the target. They add that a competition bow, with a tighter nocking point, would by itself remove this part of the spread. It is a reasonable hypothesis, not a measurement: the nocking point was not changed in any test, and the same authors point to a second cause, a draw that varied slightly from shot to shot without a clicker. A machine test from 2013 does at least show that the arrow's height on the string matters a great deal: raised by 10 millimetres, the tear in paper at 2 metres goes from under a millimetre to 40. But a nocking point moved on purpose is not a nock that wobbles, and that test is still missing.
Also phrased as: "loose nock fit"; "nock too loose on the string"; "wide nocking point"; "highs and lows from the nock"
In practice
Archers are told to use a nock that clips onto the string with a slight snap, neither tight nor loose, because a nock that wobbles on the nocking point is said to give highs and lows.
Evidence
-
2013
Context Equipment tests Published later
The author's recurve on a shooting machine, paper test: with the nocking point set where it should be, the tear between point and fletching stays under 1 mm at every distance tried, from 0.8 to 12 m; raising the arrow 10 mm on the string turns it into a 40 mm tear at 2 m, an angle of attack of about 0.06 rad, and the author writes that no archer would accept flight like that. In the model from the same paper the optimum is a gentle minimum: a millimetre of nocking point height changes the arrow's angular velocity by about 8 degrees per second. It measures how much the arrow's position on the string matters, not a nock that wobbles, and it does not look at impact height on the target.
Arrow behaviour in the vertical plane during and immediately following the power stroke of a recurve bow · James L Park
-
2019
Context Equipment tests Published later
Commissioning a shooting robot with a practice bow of about 9 kgf, at 18 m: the same arrow (809 mm, 7.5 mm diameter, 26.22 g), pulled from the target and shot again ten times, always stays inside a 160 mm circle. The authors put the vertical spread down mainly to a nocking point wider than the nock, which shifts the arrow's position slightly and therefore its angle, and partly to small differences in the draw; the nocking point was not varied, and the spread is shown only in a figure, with no numbers in the text.
Statics Investigation about Archery Robot in Drawing a Bow · Takuto Nakamura, Yogo Takada, Hitoshi Watanabe
Status history
- 2013 Not studied A machine test shows how much the arrow's position on the string matters: with the nocking point raised by 10 mm, the tear in paper at 2 m goes from under a millimetre to 40 mm. It shows that a centimetre in the vertical changes the arrow's launch a great deal, but nobody has yet tried a loose nock or a nocking point with play, or looked at what happens to impact height on the target: the claim has not been studied.
- 2019 Not studied Commissioning a shooting robot, with a practice bow at 18 metres, finds a vertical spread that the robot does not explain, and the authors put it down to a nocking point wider than the nock: the arrow sits in a slightly different place each time and changes its angle. It is the first time the question appears in the literature, but as a hypothesis: the nocking point was not changed and the spread has another possible cause as well, a draw that was not always the same. There is no measurement that puts the claim to the test.
Related
Related articles
- Fishtailing and porpoising: what arrow flight saysDoes your arrow wag sideways or wave up and down? What causes fishtailing and porpoising, which to fix first, and how to confirm it with a bare shaft test.
- Why do my arrows go left, right, high or low?Where your arrows land is a report: how to read impact patterns, and what the measurements say about the sight, the grip, bow torque and launch speed.
- Bow tuning in archery: how to tune your bow, backed by scienceBow tuning and the research: spine, centre shot, button, nocking point, brace height and tiller. What models and machine tests show, and how precise you need to be.
Research lines
Cite
Campagna, M. (2026). If the nock is loose on the nocking point, the arrow changes its impact height (Version 2). In Evidence Registry. Retrieved 16 October 2026, from https://matteocampagna.com/en/registry/equipment/loose-nock-vertical-spread
@misc{campagna2026_incoccolargodispersioneverticale,
author = {Campagna, Matteo},
title = {If the nock is loose on the nocking point, the arrow changes its impact height},
year = {2026},
howpublished = {Evidence Registry, matteocampagna.com},
url = {https://matteocampagna.com/en/registry/equipment/loose-nock-vertical-spread},
note = {Version 2; accessed 2026-10-16}
}
Follow this claim
RSS is an address you paste into a feed reader: each time this claim changes status, adds a year to its history or is revised, a new item appears there.
Registry updates by email
At most one email a month, sent only when something has changed: claims that change status, new claims, Lab predictions registered or resolved, new studies and new books.
Sign-ups are handled by Systeme.io, the service that runs the newsletter. Every email has a link to unsubscribe with one click.
Other claims in this domain
- CorroboratedAlong its flight the arrow loses an appreciable part of its launch speed12 studiesStatus since 2011
- CorroboratedAs it leaves the bow, the arrow flexes and snakes around the riser instead of leaving straight19 studies · 47 archers measuredStatus since 2012
- ReportedA camera-based scoring system misreads some arrows: the ones barely sticking out and the ones that shift the target face7 studies · 2 archers measuredStatus since 2017
- ReportedA chest band with fibre optic sensors measures breathing and mean heart rate with small errors, and an archer can wear it while shooting2 studiesStatus since 2019
- ReportedA compound bow stores between 70 and 100 joules and sheds about two thirds of the force at full draw4 studiesStatus since 2015