Bags or bipods?

[TheOTHERmaninblack]

Harmonics are what determine accuracy (to a large extent). This is why "pet" loads cannot be reliably mass produced by ammunition manufacturers. That being said, yes, the barrel is going to move as the bullet travels down the tube. But so long as it moves in the same manner and to the same degree (harmonics) the bullet will consistently leave at the same point in the travel. Which means that accuracy in the age of glass is far less a function of barrel length than it was in the days of irons.