Need help with headspace bushing size

[TheGerman]

So I was looking at getting a Hornady headspace bushing to aid in bumping back some 8mm brass but came across an issue. I looked at their sizing information and there is no 8mm Mauser listed. Kind of odd as they list/make tools in 8mm Mauser otherwise.

Here is the Hornady information:

http://www.hornady.com/assets/files/catalog/2009/69-70_precision_gauges.pdf

I looked in my reloading manuals and it seems (if I am looking at the right measurement) that the datum point of the 308 WIN is .400 and the 8mm Mauser is .392. Seeing as how Hornady makes these gauges in .375 and .400 for this range, is is safe to assume the .400 bushing will work?

I have an email into Hornady about this, but wanted to see if anyone know this firsthand.

Thanks

 

[vman]

Re: Need help with headspace bushing size

I assume it would be either bushing C or D...

Just try one out and see what happens.

Do you have the set or only one bushing?

 

[TheGerman]

Re: Need help with headspace bushing size

Was looking to order it. I have neither C nor D, and know I need to order the one for 308WIN but wanted to verify what I'd need for 8mm Mauser before placing my order so that I'm not paying shipping twice.

 

[vman]

Re: Need help with headspace bushing size

Mmmm dont have an 8mm Mauser otherwise id measure it for you and tell you which one works best... sorry mate

 

[TheGerman]

Re: Need help with headspace bushing size

No problem, I appreciate it.

I have an email in to them and may call them as well.

 

[Fuzzball]

Re: Need help with headspace bushing size

Measureing "headspace" with any case gage for adjusting a sizer only needs a comparitive measurement, not an absolute. Therefore, measuring to any one point on the fired and resized case shoulder is as good as any other point.

 

[Short Round]

Re: Need help with headspace bushing size

I called Hornady on a similar question. Can't remember if I was asking about .303 British or 7.62x45r but they pretty much said to use any bushing that fits on the slope of the shoulder.

Of course those are both headspaced on the rim so they didn't have a SAAMI number for the shoulder to give me.

ETA- I just took a walk to the "office" and tried my Hornady kit on a piece of once fired FN 8mm Mauser. The .400 looks like the better fit than the .375 bushing. The .400 is about a 1/3 up from the case body/shoulder junction. The .375 was just about on the neck, maybe 1/5th or 6th down from the neck/shoulder junction.

FWIW some of the factory datums are out toward the case body on the shoulder. The 8mm has a darn short shoulder to boot.

 

[jonaddis84]

Re: Need help with headspace bushing size

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">Measureing "headspace" with any case gage for adjusting a sizer only needs a comparitive measurement, not an absolute. Therefore, measuring to any one point on the fired and resized case shoulder is as good as any other point. </div></div>

Correct, you arent measuring to the datum line with the hornady set, or else they would have to include a different comparator for every single case made. As long as it fits over the neck, and is somewhere around the middle of the shoulder you will get a good comparison measurement for before and after bumping.