Adjusting your nock fit on the bow string will massively change your tuning in archery. It is also important to make sure the arrow fits on the bowstring properly for safety. It’s dangerous to shoot with a fit that is too loose or too tight on the string.
If the nock is too loose, the arrow could fall off the string during the shot. If the nock is too tight, over time it could cause the nock to crack. This could lead to the nock exploding when you release. Both examples are dangerous.
It’s important to get your nock fit correct before you start any tuning, and you should re-tune your bow if you change it. You can read more about tuning your bow in our guide How To Tune A Recurve Bow.