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Help! Hornady Headspace Gauge???

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Old 01-21-2014, 01:37 AM   #11
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Originally Posted by mseric View Post
NO, you are not correct and this is very dangerous.

First, The Hornady gauge is not precise enough to compare to SAAMI specs. It is just hole in a chunk of aluminum called a Comaprator. It is used to Compare your Fire brass to your sized brass. Not To SAAMI.

Second, sizing your cases .030 less than a fired case is almost impossible. If your rifle expands the case +.030 you would have a defective rifle.

Third, The SAAMI specs for the 223 are not 1.437. In fact the SAAMI spec are never a specific set number, they have a "Range" of number. In the 223 that "Range" is 1.4666 - .007. That would mean the SAAMI spec are 1.459 - 1.466.
If you wish to use SAAMI specs than your can set your dies up so the Hornady Gauge measures anywhere between 1.459 to 1.466.

Your fired brass measures 1.467 or .001 more than SAAMI. Setting up your FL die for a .002 or .003 bump will put you right into SAAMI specs.

A .030 bump will put you over twenty thousands to short.
Mseric, YOU are correct and I am not. I'm laughing because I called Hornady tech on the way home from work, and when I get home I saw your post. Hornady said the same thing. The Hornady head space gauge is more for comparison then an "absolute" reference. In other words, as you said it's a peice of aluminum and even Hornady said you would get different readings from different Hornady gauges. It's more for comparing (using the SAME gauge) brass before and after firing in the same rifle.

Apparantly, to do this right (and that's what I want to do, I'm new and want to learn the right way and do it the right way) I really should get a caliber-specific steel case gauge such as the Wilson or the Dillon gauge.

Also, interestingly enough, I measured some brand new Hornady rounds and got that same 1.468 measurement as I did from the fired case. So as you said the bump is not 30 thousanths, but only a few thousands.

Also, interestingly enough, is that the SAAMI drawing shows BOTH measurements....the 1.438 AND the 1.466. So, what's the deal with THAT?

At any rate, I'm going to buy a (steel) SAAMI caliber-specific head space gauge. Any recommendations as to which brand?
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Old 01-21-2014, 02:33 AM   #12
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Also, interestingly enough, is that the SAAMI drawing shows BOTH measurements....the 1.438 AND the 1.466. So, what's the deal with THAT?
If you look close you will see that the 1.438 is at the junction of the case body and the shoulder.

The 1.466 is further forward at the Datum line where the shoulder measures .330 in diameter.. Your "Comparator" has a .330 hole in it and measures off that "Datum" line, not the body shoulder junction.
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