Its my understanding that freebore is merely a space directly in front of the case neck that has no rifling in it for a given distance. Then what is leade? Whats the purpose of them and why does Weatherby use a long freebore?

Not sure about leade but weatherby uses freebore to reduce pressure in there loads

quote:

Originally posted by Scott:
Its my understanding that freebore is merely a space directly in front of the case neck that has no rifling in it for a given distance. Then what is leade? Whats the purpose of them and why does Weatherby use a long freebore?

It is my understanding that leade is the transition area into the rifling, commonly called the throat. The angle of which is ground into the reamer used to form the chamber.

I may be wrong though..........

Jim

The answers you've gotten pretty well add up to the whole story:

Freebore is the portion of the barrel immediately in front of the chamber which is without lands and is approximately groove diameter (although in practice it must be a tad larger, since a .308" bullet won't slide into a .308" hole). The freebore section may be as little as an eighth of an inch or as long as half an inch or more in "freebored chambers". The land-free section effectively increases the volume of the gas expansion chamber, thus allowing the use of slightly heavier powder charges in the same cartridge without inceasing pressures. This also, at least in theory, allows higher velocities at the same pressures. The theoretical downside is that the bullet starts its travel through a slightly oversized tube which may allow it to tip slighlty or otherwise do something that is not conducive to good accuracy. In other words, freeboring is an effort to get a free lunch, which may (or may not) be paid for in loss of accuracy and usage of additional powder.

The leade is the beginning of the riflings (lands). They normally taper at an obtuse angle from zero to full height (about .004" in most bores) over the course of a fraction of an inch.

Some proprietary cartridges (like Weatherby) will specify a particular freebore, and maybe even a leade angle. Most SAAMI standards do not specify a freebore that is any longer than necessary to allow a typical bullet to be seated to SAMMI overall length without contacting the lands (leade, in this case).

The best that I can tell...

From the left to the line is the rifling.

Between the lines is the leade.

To the right is the freebore and chamber.

8x57 Mauser

Bill What ya been doing, BBQ`ing in that barrel?? Clean it up!!

"A picture is worth a thousand words".

Thanks for the great illustration, Bill Mc!

Hey Bill Mc, What kind of event caused you to end up with "a sectioned barrel"?

This some kind of "Sako Kit Rifle" that now comes pre-exploded?