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What do you consider the freebore?

In my experience the LEAD dimensions on the print is the Free-bore (length & diameter).
Which on the OP's print is 0.2350" in length and 0.2844" in diameter.
It is the parallel portion after the neck ramp and before the throat (angled).
Edited in RED the LEAD/Free-bore from the OP's print:
Donovan


FreeBore2.png
 
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Call the rifling angle at its origin whatever you want. Here's what most I've heard say as well as SAAMI:

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.
 
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If you order a zero freebore reamer, it will still have the angle at the end of the neck and whatever leade angle you specify. I have gotten along using term freebore to describe the parallel cylindrical section that starts at the front of the angled transition from the chamber neck to the very beginning of the leade angle. As a practical matter I use a reamer drawing form and fill in the blanks so that there is no mistaking my intent.
 
on the opening print free bore is lead/235.
other companies use different terms, but the number is the same.
and yes the taper from neck to bore is not counted in free bore/lead.
what donovan and boyd have said

BoydAllen said:
If you order a zero freebore reamer, it will still have the angle at the end of the neck and whatever leade angle you specify. I have gotten along using term freebore to describe the parallel cylindrical section that starts at the front of the angled transition from the chamber neck to the very beginning of the leade angle. As a practical matter I use a reamer drawing form and fill in the blanks so that there is no mistaking my intent.
Click to expand...
 
Dimension H is part of the chamber neck diameter. The chamber front end is dimension G.
Dimension G is the back end of the free jumpbore. Dimension G to H is the chamber mouth. Dimension I is the origin of the rifling and front of the freebore.

As I reason this out.

I think these inner barrel places have the greatest disparity of names.
 
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In true gun speak, freebore is the length of the leade and the throat combined; that part of the barrel that is free of any rifling forward of the case mouth.
The leade and throat are not always easy to distinguish. A tapered leade is easy to recognise and it runs right into the parallel sided throat.

Does a straight sided throat have a leade?

Well technically no, as this can be called a parallel sided throat with no leade.

Why everyone calls it freebore is unclear, and maybe due to misunderstanding the true definition of leade and throat.’
Bart B. said:
The distance from case mouth to the chamber mouth, where freebore starts, has oft times been termed "case mouth clearance" like the "case head clearance" from bolt face to case head. Both with cartridge full forward in the chamber when fired.

I've heard that rimmed and belted cases can have "shoulder clearance" when fired.

If you check SAAMI chamber specs, you may learn some cartridge chambers' have zero freebore. 300 Win Mag and 30-06, for example.
Click to expand...
According to my SAAMI drawing the 300WM has a throat, albeit a tapered leade, that measures .2976” in length. It measures 2.9545” to end of throat from end of chamber 2.6569”.
So, zero freebore is not exactly true as the freebore is the ENTIRE portion of the barrel forward of the chamber end free from rifling, whether it’s tapered or not.

Cheers.
:)
 
dmoran said:
In my experience the LEAD dimensions on a print is the Free-bore (length & diameter).
Which from the OP's print is 0.2350" in length and 0.2844" in diameter.
It is the parallel portion after the neck ramp and before the throat (angled).
Edited in RED the LEAD/Free-bore from the OP's print below:
Donovan



View attachment 1041147
Click to expand...


When you order a reamer, ^^^this^^^ "U & V" is the dimension that the reamer maker calls 'free bore'. Whatever length you tell them, shows up in this box on the print.
 
no,
MagnumManiac said:
In true gun speak, freebore is the length of the leade and the throat combined; that part of the barrel that is free of any rifling forward of the case mouth.
The leade and throat are not always easy to distinguish. A tapered leade is easy to recognise and it runs right into the parallel sided throat.

Does a straight sided throat have a leade?

Well technically no, as this can be called a parallel sided throat with no leade.

Why everyone calls it freebore is unclear, and maybe due to misunderstanding the true definition of leade and throat.’

According to my SAAMI drawing the 300WM has a throat, albeit a tapered leade, that measures .2976” in length. It measures 2.9545” to end of throat from end of chamber 2.6569”.
So, zero freebore is not exactly true as the freebore is the ENTIRE portion of the barrel forward of the chamber end free from rifling, whether it’s tapered or not.

Cheers.
:)
Click to expand...
 
'Tis interesting that firearms industry members subscribing to, or not, SAAMI standards, and their customers who do or don't, are not always on the same page, singing the same song nor using the same names, terms and conventions based on one glossary.

Example:
the freebore is the ENTIRE portion of the barrel forward of the chamber end free from rifling, whether it’s tapered or not.
Click to expand...
Versus
SAAMI glossary...
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.

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 toprovide clearance for the seated bullet. Also called Throat or Ball Seat.
Click to expand...
Cylindrical means its sides are parallel. Conical means its sides are tapered
 
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Ledd Slinger said:
Oh no... The Vocabulary and Grammar police found another thread. Everybody study the SAAMI manual before replying or you'll get a citation from Bart B...:rolleyes:
Click to expand...

What? You mean there's a limit to overthinking something as simple and straightforward as freebore? I think we need a couple more pages to define the word bore and then a few more pages to add the word free to it. s-beat-dead-horse.gif
 
hogpatrol said:
You mean there's a limit to overthinking something as simple and straightforward as freebore?
Click to expand...
No, there's not as long as we all define it differently.

I pointed out the industry standard. Treat it like you do motor vehicle traffic laws.
 
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