EDG
01-22-2015, 02:19 PM
For measuring the neck diameters and base diameters of sizing and form dies I use a set of SPI or equivalent gauge pins in .001 increments. I formerly used a set of Starrett small hole gauges that are measured using a micrometer. I got lazy and thought the pins would be much better. The pins are better but I remeasured some dies that were originally measured using the small hole gauges and my results were very close- within .001 in most instances.
I measure shoulder diameters by measuring the shoulder of an annealed sized case that has been ran into the die multiple times. These numbers are compared to fired cases and chamber casts. You will find the die brands that squeeze your brass unmercifully and there are at least 2.
Spread sheet data
I have a spread sheet of all of my dies that I have measured - so far about 100. These are dies that are used for sizing and forming or have potential use for forming. Many of the dies are measured just to find the one that leaves the case as large as possible while still chambering - (the dies that are largest in the base and shoulder).
In some cases (very bad pun not intended) my bore diameters may require a bullet that could be larger than accepted by the seater die's bullet guiding section. This will allow you to select a larger die or point you toward lapping your die out .
All of this measuring and data recording allows me to select the best dies for a new project by simply looking at the data without having to measure my dies every time I start a new case forming project. If I don't have the right die for a future project I can begin looking for it or plan on making it.
Case body datum length
While I have not progressed toward this I intend to add a case body datum length to my die measurements.
This will come from my Hornady case gauge tool. However some of my Hornady adapters do not have a sharp edge so the dimension found may vary from the SAAMI drawing. The Hornady tool is excellent for making comparisons but the edges of the adapters need to be sharp if the numbers give an accurate comparison to a SAAMI drawing. I have a few sets of gunsmith chamber headspace gauges. When the Hornady tool is set to a headspace gauge and is zeroed the numbers are an accurate comparison to a SAAMI drawing. To correct my tool for use to comparing to SAAMI measurements I need to replace a couple of my adapters.
Other important items
Top quality 0 to 1" micrometer
Tubing mic or multi-anvil mic
Dial Calipers
I measure shoulder diameters by measuring the shoulder of an annealed sized case that has been ran into the die multiple times. These numbers are compared to fired cases and chamber casts. You will find the die brands that squeeze your brass unmercifully and there are at least 2.
Spread sheet data
I have a spread sheet of all of my dies that I have measured - so far about 100. These are dies that are used for sizing and forming or have potential use for forming. Many of the dies are measured just to find the one that leaves the case as large as possible while still chambering - (the dies that are largest in the base and shoulder).
In some cases (very bad pun not intended) my bore diameters may require a bullet that could be larger than accepted by the seater die's bullet guiding section. This will allow you to select a larger die or point you toward lapping your die out .
All of this measuring and data recording allows me to select the best dies for a new project by simply looking at the data without having to measure my dies every time I start a new case forming project. If I don't have the right die for a future project I can begin looking for it or plan on making it.
Case body datum length
While I have not progressed toward this I intend to add a case body datum length to my die measurements.
This will come from my Hornady case gauge tool. However some of my Hornady adapters do not have a sharp edge so the dimension found may vary from the SAAMI drawing. The Hornady tool is excellent for making comparisons but the edges of the adapters need to be sharp if the numbers give an accurate comparison to a SAAMI drawing. I have a few sets of gunsmith chamber headspace gauges. When the Hornady tool is set to a headspace gauge and is zeroed the numbers are an accurate comparison to a SAAMI drawing. To correct my tool for use to comparing to SAAMI measurements I need to replace a couple of my adapters.
Other important items
Top quality 0 to 1" micrometer
Tubing mic or multi-anvil mic
Dial Calipers