What exactly is "freebore"?

[Jeff, CA]

I keep hearing this term, especially in reference to Weatherby rifles. Somehow, I think it's a non-technical term, like "magnum".

AFAIK, there are 2 types of chamber throats: funnel-shaped and parallel. Where does "freebore" fit into this, if at all?

All Norma-designed cartridges have parallel throats. Since they collaborated with Weatherby on his cartridges, does this simply mean Weatherby cartridges have parallel throats?

 

[3 gun]

Freebore - (aka ‘barrel throat’) The distance a bullet must travel between chamber and bore before its bearing surfaces contact the lands of the rifling, the purpose being to delay resistance, hence prolong pressure built-up. It cannot be too much, however, as that can cause instability in the bullet. This distance will vary from rifle to rifle, as well as according to the preference of the handloader, as some prefer the bullet to touch the lands, while others prefer it to be further away. Care must be taken not to make this distance too great, as this will adversely affect accuracy. It is not advisable to have the bullet touch the lands, either, as that can increase pressure levels significantly.

A detailed look can be found HERE

 

[Erich]

And here I was ready with a Lynrd Skynrd joke!