What is a free-bore?  I came across a forum posting by ‘RSE
Custom Guns’ explaining what a free-bore is:  Free bore is just
that, it is the area ahead of the bullet ogive in a rifle barrel
to which there is no rifling, once the cartridge is fired the
bullet travels freely in the barrel until the bullets ogive
contacts the rifling, hence free bore.  Why add more free bore:
The case for free boring is made this way, if you have a bullet
seated deeply in a rifle case, the bullet is actually decreasing
case capacity which in turn lowers the over all velocity of that
imparticular bullet / case loading.   How much can it help:
More here.   Steve Johnson   More In: Rifles     •
http://www.calivc.com Heath G      Great write up.