True or False

[3GRacing]

Leade, freebore and bullet jump, all refer to the same measurement.

 

[retired]

no
leade and freebore are characteristics of a chamber.
bullet jump is a characteristic of a loaded round of ammo in a specific chamber.

Leade, freebore and bullet jump, all refer to the same measurement.

 

[Sniper338]

negativo ghost rider

 

[hoz53]

negativo ghost rider

do you mean bore rider?

 

[JohnHenry]

Leade, freebore and bullet jump, all refer to the same measurement.

FYI:
http://bisonballistics.com/articles/an-introduction-to-rifle-chambers

http://www.bergerbullets.com/setting-loads-optimum-accuracy/

 

[spife7980]

Leade, freebore and bullet jump, all refer to the same measurement.

The throat is the area from the case mouth to the begining of the full rifling in the barrel.
Freebore is the cylindrical area in front of the case neck that has the lands completely bored out and removed.
The leade is the angled transition from the smooth area of the throat into the raised lands of the rifling.

Jump is the distance from where the bullet is seated in the case to where it engages with the lands of the rifling when fired.

 

[3GRacing]

Thx for the replies. Searched the net, got confused, should of asked here first- thx again...

 

[dcali]

This one of those things that varies based on who you are talking to. Freebore seems pretty much unanimous - it's the unrifled portion of the bore ahead of the neck, but before the conical section that leads to the fully rifled bore. Leade, to me, means the conical section. But other people define it other ways. Same with throat. Some say it's freebore plus leade. Others say it's the same as leade. And still others say it's what I call freebore.

It would be nice if we'd all get on the same page. The best approach is to not use the term "throat", and stick to "freebore" and leade angle, as those definitions are universal as far as I can tell, and they tell you everything you need to know.

The reamer manufacturers make things worse - most of the drawings seem to label the line at the end fo the free bore as "leade" (or "lead"), and the line at the end of the angled section (what I call "leade") as "throat". It's really unclear, and just confuses things.

Jump has nothing to do with the chamber at all, and is just the axial distance from the bullet to the lands. (everyone seems to agree on this). "Jam", on the other hand, has different meanings. Some say it's the condition in which the bullet just touches the lands. Others say it's basically negative jump. The former is common with benchrest shooters. The latter is more common with everyone else.

 

[3GRacing]

Ty damoncali, I found the bisonballistics article later last night, made it clear to me.

 

[M-61]

No. You can change the 'jump or 'jam'. The free bore and leade are what was machined (? reamed, cut ) into the barrel.

 

[Ron Blain]

Leade, freebore and bullet jump, all refer to the same measurement.

In an effort to have uniformity with definitions throughout the industry the nice people at SAAMI have a published glossary:

LEADE (LEAD)
That section of the bore of a rifled gun barrel located immediately ahead of the chamber in which the rifling is conically removed to provide clearance for the seated bullet. Also called Throat or Ball Seat.

FREE BORE
A cylindrical length of bore in a firearm just forward of the chamber in which rifling is not present. Associated with bullet jump.

BULLET JUMP
The distance that a bullet must travel from its position at rest in the cartridge case to its initial engagement of the rifling.

They do mention that Free Bore is associated with bullet jump but none of the three actually share the same definition.

Ron

 

[joshb]

do you mean bore rider?

I don't have one of those. Should I get one and where? Sounds expensive but if it'll help me hoot better, oh well!

To the op: False!
Thanks, spice. A picture is worth a thousand posts!