Quote Originally Posted by olegburn View Post
what is "tuning" or vibration?
Isn't bullet long gone (left the barrel) before anything that can affect it ?
.
the barrel starts to vibrate the instant it is fired. up and down ( and other directions) as the bullet travels down the barrel. Harmonic frequency. Changes in bullet weight, powder burn rates, primers, speed and every thing else you can think of all effect the rate of oscillation. One part of tuning is trying to get the bullet to exit the barrel on one of the stops where the barrel quit moving to change directions of its wiggling travel. Hand loading takes advantage of this by allowing you to for instance pick a bullet you like that may not be to great in your gun as a factory load and allow you to change the powder charge to change the vibration frequency and tighten up the group size..