Some how, bad information has been passed down from archer to archer for many years on the correct method to bare shaft tune. Some might be familiar with, or heard of a technique of bare shaft testing that requires getting close to your target and analyzing nock left/right/up/down patterns for tuning purposes, that is not a good method and causes great confusion! The correct way is bare shaft "planing", or determining adjustments based on bare shaft groups in relation to identical fletched shafts at longer distances.
As stated above, an arrow balances forward of center, and if everything is perfect, fletching is not required for accurate arrow flight. A well tuned shaft always goes where it's pointed, fletched or not.
To get started, it's easiest if you have at least several close to correct sized shafts from the chart and several above and below the recommended size also. That is not always possible so let's just say you only have the recommended size from the chart. Your bow should be set up exactly the way you intend to hunt with it. All silencers installed, brush buttons, arrow rest, bow quiver, ect....
Install field tips of the same weight as the broadheads you want to shoot if you have a choice. If you are stuck with only one size shaft, you may be forced to shoot tips heavier or lighter than your desire. NEVER BARE SHAFT BROADHEADS! Field tips/target points only. Broadheads will act like fletching on the wrong end and wild flight can result.
Now to get started, step back 15 or so yards and start shooting 3 or 4 bare shafts mixed with 3 or 4 identical fletched shafts aiming for a spot. Odds are they are not going to fly very well so we need to start making adjustments to straighten them out.
You are going to make adjustments based on where the groups are in relation to eack other, not on whether the nocks are kicking one way or another. We want to take care of any up/down problems first. If the majority of your bare shafts are grouping high or low of where the majority of your fletched arrows are, the nock point needs to be adjusted.
Ignore left and right problems at this time. If your bare shafts are grouping lower than you fletched shafts, lower your nock point a tiny bit, maybe 1/32" and shoot several more arrows. If you lower your nock point all the way to zero and they are still hitting low, your nock point was too low to start with and the back of the arrow is "kicking" off the shelf, giving a "low" indication! If they impact (group) higher, raise your nock point.
Once your bare shafts are grouping close up/down with the fletched shafts, it's time to work on any left/right problems. If the majority of your bare shafts are impacting (grouping) left of the majority of your fletched shafts, your arrows are too stiff.
To correct this you have several options. The easiest is to increase point weight one step and try again. It's possible you may have to go from a 125gr tip to 190gr to get good flight! Another option if you have a thick side plate on your arrow shelf in the sight window is to reduce the thickness of that side plate, moving the arrow closer to centershot, and test again.
It's also possible you may never get good flight if they are way too stiff and you will be forced to get new shafts of a weaker spine. Hopefully that won't be the case. If the majority of your bare shafts impact (group) right of your fletched shafts, they are too weak. Reduce your tip weight and try again, or build out your side plate further away from centershot. You can shorten your arrows 1/2" at a time which will make the arrow stiffer. Again if the problem can not be corrected, new shafts of a higher spine may be needed.
Remember to never base adjustments on one or two shots, shoot many shots mixing bare and fletched shafts and average the relationship between the groups. For example if 5 bare shaft shots went left of the fletched shafts, and one went right, adjust for a shooting left indication. Change only one thing at a time and evaluate the results. Changing from a 2018 to a 2117 for example is TWO CHANGES, not one!
You have changed spine and centershot! Any changes you make to the bare shafts, make the same changes to the fletched shafts! The bare and fletched shafts must be identical. Once you are getting fairly satisfied, step back to 20 yards and start shooting several fletched shafts and bare shafts....Repeat the tuning process starting with nock point adjustments.
A properly tuned set up, bare shafts and fletched shafts will group together out to 30 yards or more. Expect the bare shaft groups to be somewhat larger then the fletched groups for obvious reasons! The better your form is, the tighter the groups will be and the farther away you can maintain good groups, and finer tuning can be accomplished.
The most forgiving arrow to shoot will actually show a slightly weak/slightly high nock point indication. In other words, at 20 yds or more, bare shafts grouping a little low and right is perfect because fletching makes a shaft react slightly stiffer. Totally confused? Here is an overview: