Freebore?

[Riverfox]

New to rifle reloading and would like someone to enlighten me. What is freebore and why and when is it important to use that knowledge?

Thanks in advance

 

[Supersubes]

Freebore is the cylindrical portion of bore just forward of the chamber(end of your case neck). In most match chambers, it’s usually .0005-.001 over bullet diameter. The purpose is to accommodate the full diameter portion of the bullet which protrudes beyond the case neck. Without freebore, the entire bearing surface of the bullet would need to be buried in the case neck. That can be fine in a small bore varmint cartridge which uses a very short bullets. Won’t work on a heavy for caliber match bullet.


Edit: For a mag fed tactical rifle, proper freebore will allow the bullet to be seated out as far as possible so as not to encroach on the powder space, still fit in the magazine, and have some space left over for bullet jump.