Rifle Chamber Jargon Question

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carnaby

carnaby

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Does anyone use a name for the section of the rifle chamber between the end of the neck and the start of the freebore? I've heard *step*, *forcing cone*, and nothing else. Neither seems right, especially forcing cone... what does that little shoulder force?

Every other part of the chamber has a well enough defined name. If it doesn't have one, it should. Maybe *neck step*, *neck shoulder*, *freebore step*, *throat step*, or ...?
 
I don't think you understood my question. I'm looking for the name of the step in diameter from the neck to the freebore. The diagram below calls it the *second shoulder*.

Chamber2.jpg
 
SAAMI - Key wording- tapered portion
THROAT


The tapered portion of the bore of a barrel, immediately ahead of the chamber which is sized to provide clearance for the bullet of the loaded cartridge. Also referred to as Leade or Ball Seat and is associated with Free Bore. See Free Bore.



Also Known As: Leade, Ball Seat

Related Terms: FREE BORE
Click to expand...
 
Look at the diagram in my last comment. The thing labeled "second shoulder" is all I am interested in. I already know the shoulder, the neck, the freebore, the leade, and the throat.
 
It's definitely not the throat. The throat is synonymous with the leade, according to the SAAMI page you linked to. This is the section BEFORE the freebore and leade/throat. It is very short, cut at a 45 degree angle. In your drawing it starts at 2.025" and ends at 2.0488" for a total of 0.0238". The throat starts at 2.1388 and ends at 2.3025. It's not the throat and it's not the free bore. It doesn't have an official name I don't think.
 
It's called a leade and is the conical transition or step between the throat and the rifling. It may be cut to varying degrees of taper. While such taper is not terribly important in modern high pressure rifles, it is, for example, a subject that occupies much "discussion" with the paper patch community.

For more:
https://bisonballistics.com/articles/an-introduction-to-rifle-chambers
 
Ugh! You guys need to read closer. Please make sure you understand my question before answering. IT IS NOT THE THROAT
IT IS NOT THE LEADE
IT IS NOT THE FREE BORE

It is the section just before the free bore at the very end of the neck.
 
You are referring to where the chamber neck ends and transitions into the lead. I've always considered this part of the neck. Since it's beveled I can see why it's referenced to as a second shoulder. But it's not the shoulder, just a angled cut for transitioning to the leads. Not sure why they are calling it something it's not.
 
carnaby said:
Ugh! You guys need to read closer. Please make sure you understand my question before answering. IT IS NOT THE THROAT
IT IS NOT THE LEADE
IT IS NOT THE FREE BORE

It is the section just before the free bore at the very end of the neck.
Click to expand...
Go ask @MachIVshooter lol I think he's about the most likely to know what term your looking for, cause I sure don't.
 
LoonWulf said:
Go ask @MachIVshooter lol I think he's about the most likely to know what term your looking for, cause I sure don't.
Click to expand...

The step ahead of the freebore area is a nameless feature.

This is the correct answer:

GBExpat said:
Interesting. I learned long ago that the "Throat" is composed of the Freebore + the Leade (a term not even included on that diagram). It appears that the Leade is labeled as the Throat, above.
Click to expand...

Free bore means exactly that, a part of the bore in which the bullet is "free" of contact with the bore. Any distance ahead of the case mouth & before the leade is free bore. The leade is the transition from free bore into rifled bore, which may include a smooth groove diameter or tapered section.
 
Nameless feature is what I thought. I would like it to have a name. Possible, MachIVshooter, that you have a nickname for it? Second neck and forcing cone are unsatisfying.

I already know exactly what all the named features are and I understand their definitions perfectly well. This is why I would like the nameless feature to have a name because it does come up in discussion and you can see the trouble. It took 10+ replies before someone finally knew what I was getting at, and even then you lectured me on free bore and leade/throat.
 
The step down from neck diameter to throat diameter is the Chamber Mouth, Mirror image of the case mouth.

Terms are slippery on the internet, but I take the Throat to be the cylindrical section, usually at or slightly above groove diameter, from the Chamber Mouth to the origin of the rifling. It is only Freebore if it is longer than its diameter. I call the taper from throat into full height of lands the Leade.
Others, many here above, use Throat, Leade, and Freebore interchangeably. OK.
 
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