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shinny
06-02-2013, 12:06 PM
Ever wonder when someone says "I use .002 NT" what that actually means.:confused:

Most folks I have spoken with about this subject say they: Take Bushing size, minus the turned dimension of their necks (X 2), to determine this number.

E.G. Necks Turned to .0085 and a .258 bushing should equal .002 NT.



Is this absolute or relative?
Can this number be used reliably?
Anyone ever verified this with pin gages?
Does this dimension change with multiple firings?


I have done some testing on this subject and wonder what others have found. All opinions, ideas and feedback welcomed.

Hunter
06-02-2013, 04:24 PM
You must also know the diameter of the chamber neck.

Can you explain why the diameter of the chamber is relevant?

Boyd Allen
06-02-2013, 05:10 PM
The best way to come up with neck tension is to carefully measure the diameter of the sized neck, seat the bullet that you are using, and remeasure the OD of the neck over the largest diameter of the bullet that falls within the case neck. IMO measured beats calculated every time. Just be sure to measure the empty neck very carefully, they can easily be compressed by the leverage afforded by by the 40 tpi pitch of a micrometer.

alinwa
06-02-2013, 05:50 PM
The op poses a valid question, one to which there is one valid answer, all math aside.





Lissen to Boyd......

Read the post,

try his method,

UNDERSTAND what he's saying and you'll know exactly what ".002 NT" means.

If you don't, read Boyd's explanation again.

And again

:)

The math is really irrelevant, simply a product of YOUR particular variables, whereas ".002 NT" is a description of a relative constant.

al

shinny
06-03-2013, 08:11 PM
The op poses a valid question, one to which there is one valid answer, all math aside.





Lissen to Boyd......

Read the post,

try his method,

UNDERSTAND what he's saying and you'll know exactly what ".002 NT" means.

If you don't, read Boyd's explanation again.

And again

:)

The math is really irrelevant, simply a product of YOUR particular variables, whereas ".002 NT" is a description of a relative constant.

al

Al,

Who or what is the OP?

alinwa
06-03-2013, 10:16 PM
Al,

Who or what is the OP?

You, the original poster

shinny
06-04-2013, 08:41 AM
You, the original poster

Not up on all the Acronyms used on this site. :confused: It would be great if someone could post a listing of same.:o