At some point in the development of an archer their thoughts turn to bow tuning. So to save a lot of time and frustration here is a quick guide to everything you need to know on a practical level about bow tuning.

If you shoot a bunch of arrows at the middle of a target, They don't all hit the middle, the arrows are scattered around the target. The overall area of scatter is referred to as the "group size". Assuming the arrow group is centred on the middle of the target then the smaller the group size then the higher the score you will get. Individual archer's statistically are very consistent on the size of their groups. The GNAS classification system is based on group sizes being consistent. If they weren't the idea of a classification would be meaningless.

Let's take an example, you have two archers who are twins, both have identical bows and arrows and the exactly the same bow set ups. Both archers have the correct arrow (from the arrow manufacturer's table) and they both shoot the same number of arrows at a specific target. One archer's group size is smaller than the other. The score value of the archer with the smallest group size will be higher. The main reason for this is the archer with the smaller group size is the better archer. "Getting Better" at archery is all about reducing group size.

Now suppose you take one of these archers and make small modifications to the set up of the bow. What you find, from experience and with some theoretical support, is that with same equipment and same archer skill level changing the bow set up makes some difference the average group size. As score relates to group size, finding the bow set up that gives you minimum group size gives some benefit to scores attained.

Tuning is the process of finding the bow set up that gives the minimum group for a fixed archer skill level and equipment"

Tuning Methods

There are three tuning methods that give some practical benefit described at some level here. There are many other suggested methods which work to some extent and some that are completely useless. Basically the methods described here are the recommended methods. If you want to try some other method - well that's up to you.

METHOD A - Group Tuning

There is only one method to find the optimum bow set up to minimize groups and this is group tuning. You need to be GMB level or higher to even consider this approach. Optimum tuning setup is a function of target distance i.e. the optimum tuning set up for 30 metres will be different to the optimum tuning setup for 70 metres. As 70 metres is these days the important competition distance this is the usual distance for group tuning. The method is trial an error in a systematic way and normally follows a basic bareshaft tune (as described in Method B). Shoot a bunch of arrows, measure the group size, make a small bow modification and see whether the group is increase or reduced, action as necessary and keep going round the loop. The main set up modifications are to the nocking point and the button spring tension but changes to the centre shot and bracing height may also be made.

METHOD B - Bareshaft Tuning

With bare shaft tuning you compare the relative target hit positions of fletched and bareshaft arrows and adjust the bow set up so that the fletched and bare shaft arrow groups overlap. While the resulting set up falls quite a way short of the optimum there is an improvement to be had by this method. The method is applicable to archers at a good bowman level or higher so it is relevant to some club members. Bare shaft tuning is done on an 80cm target at a distance of 30-45 metres. A shorter or longer distance than 30-45 metres will reduce the quality of the result and at less than around 20 metres the method becomes completely useless.

There a number of good write ups on this method (e.g. see the Heretic Archer) so a bare shaft tune by numbers is given. The pre-requisite for this method is a correct sight pin alignment and a correct arrow - bow match, and a 30 metre sight mark. The bow should have had a basic set up and the archer be happy with draw weight, brace height, stabilisers etc. I would suggest using three fletched arrows and three bare shaft arrow.

1. Shooting fletched arrows only change the button spring pressure to move the arrows to the target centre.

(this roughly sets the button spring for the nocking point adjustment)

2. Shooting both fletched and bare shaft arrows adjust the nocking point so that the two arrow sets hit at the same height.

(If the bare shaft arrows hit above the fletched arrows raise the nocking point and vice versa)

3. Shooting both fletched and bare shaft arrows adjust the button spring tension so that both arrow sets group in the gold.

(For a right hand archer to move the bare shaft left towards the fletched arrow increase button tension and vice versa, for a left hand archer the opposite applies)

Job done. If the bare shaft arrow initially hits outside the blue ring then you have a clearance problem or the wrong arrow, fix this problem and try the tuning method again. If the required button spring tension ends up to stiff or too soft then adjust draw weight and try again (for right hand archer, button too soft - increase draw weight and vice versa, reverse for left hand archer).

METHOD C - The Tuning Method With No Name

The third tuning method I'm suggesting has never been written anywhere else as far as I'm aware so it has no recognised name. It uses fletched arrows only and the result in terms of tuning optimisation is not as good as a bare shaft. The results however aren't bad and the big plus is that the method can be used by pretty much any level of archer.

1. Nocking Point Adjustment

Place a horizontal line on the target (face edge/line) so that when aiming at the line the long rod is around horizontal. Adjust vertical sight mark/line position as appropriate. Place the target at around 3-4 metres distance.

Shoot some fletched arrows, aiming at the line (The line allows you to spread the arrows, if you aim at a spot you are going to smash a lot of arrows).

Check the alignment of the arrows - nock high, nock low, arrow level. Adjust the nocking point so that the arrows hit level (nock high - lower nocking point and vice versa). Arrow level or slightly nock high is acceptable. Arrow hit with nock low not acceptable. Fix nocking point and record value.

Job done. If the required button spring tension ends up to stiff or too soft then adjust draw weight and try again (for right hand archer button too soft - increase draw weight and vice versa. Opposite weight adjustment for left hand archer).

GOOD SHOOTING...

©Joe Tapley 2009