Neck sizing or shoulder bumping
- Thread starter AL PALMER
- Start date
I guess it comes down to , how some people we all know a few , that murder the English language with their words but we still know what they are trying to say . Headspace is one I use , easier to say then bolt face to datum line on a locked bolt measurement . Is there one word that is correct ?
As many probably already know, SAAMI refers to that "measurement" as the "Headspace Dimension" on their chamber drawings of rimless cartridges.
For rimmed and belted cartridges, the "Headspace Dimension" on the chamber drawings is from the bolt face to the step in the chamber that corresponds to the front of the rim or belt.
For rimmed and belted cartridges, the "Headspace Dimension" on the chamber drawings is from the bolt face to the step in the chamber that corresponds to the front of the rim or belt.
SAAMI does not list head space for the case in their drawings; they do not use a foot note indicating head space for the case. I accept that, the case does not have head space, You can call them and tell them who your are and list the reasons they should take you seriously. I will not do that, I do not have case head space gages, I have case gages, the case gage has been with us for over 75 years. And then came the Internet and reloaders that insist on rediscovering and renaming with the sole purpose of making their claim of discovery. There were reloaders before me and their will be reloaders after me, I did not invent this stuff but I continue to ask reloaders where the .002" bump came from.
Bump? It is impossible to bump the shoulder back on a case with a die that has full body case support; but on the internet anything is possible if the reloader does not understand the question.
. Guffey
Brian Pfleuger
Moderator Emeritus
BBarn said:
I actually called SAAMI about that very question, several years ago. First, we have to realize that there are two different diagrams, the chamber and the cartridge. The chamber diagram doesn't reference anything about the case, directly. On the cartridge diagram, they literally have no name or symbol for what is commonly called "case headspace" whatsoever. It is simply given as a dimension. On the chamber diagram, it is called "Headspace Dimension" but that is not a reference to the case/cartridge at all, but the chamber.
However, the gentlemen also told me that SAAMI is well aware that not only the general public but also major manufacturers, such as Hornady and many others, refer to the dimension as "case headspace" and they (SAAMI) have no trouble with that designation at all.
In fact, the only person (or organization) I've ever known of who does have a problem with the term is Mr F. Guffey.
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Thank you
You are the third member of this forum that claims they called SAAMI. The first one had too much time invested in trying to convince reloaders SAAMI listed head space on their case drawings. I insisted SAAMI did not list head space on their case drawings and they did not list head space footnotes on their drawings.
Before that there was the rash and rush to change the name of tools like head space gages. Forum members were unaware of the attempt to manipulate the search engine because reloaders did not know the difference between a gage that measured the length of the chamber from the shoulder to the bolt face and a gage that measured the length of a case from the shoulder to the case head; SO? everything became a head space gage and for that to happen the case had to have head space.
And then before that Hornady/Sinclair wanted top billing so they moved from the comparator to the head space gage. That one was easy because all they had to do was get it past internet reloaders that did not have a clue the datum does not have a radius. The radius makes the tool a comparator.
Again: Reloaders fell for the digital head space gage, I said at best it was a comparator, Starrett and other manufacturers of precision call it a dial indicator stand; and reloaders call it a head space gage.
F. Guffey
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