Bare shaft tuning was probably used first by target shooters to fine tune light, shafts with small feathers, or vanes. Bowhunters used heavier equipment and larger feathers, and were rarely concerned with bare shafting.
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Most testing was done at 2-10 yds. Shooting further was not necessary. Testing was done with a spot the size of a dime, and shafts of various lengths (1/4 +/- inch) and sometimes different weight in points. A fletched arrow was used as a control. The objective was to find the best shaft, weight, length, etc.
In theory, you want the bare shaft to hit the feathered shaft, and one or two test arrows usually gave the best results.
Because straw, hay, or cedar bales were commonly used, grain in the bale often affected how the shaft entered the bale, another reason to stay within 30 ft.
Shooting a center shot bow made it easier for target shooters. Early bowhunters shot non-center shot bows and paradox was a problem with older equipment.
If you can shoot a tight group with bare shafts around a fletched arrow, at 10 yds, it is time to fletch some arrows.