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Old July 23, 2010, 09:43 PM   #1
brmfan
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Join Date: October 21, 2008
Posts: 557
Am I measuring this wrong??

Okay... got a Sinclair bump gage today to help set my FLS die more accurately. Checked the SAAMI minimum headspace for a .308 and it was 1.6315". After zeroing (General Tool brand digital caliper from Lowes... just bought it yesterday), I checked an unfired SA ball, a Malaysian L2A2 ball round, and a 175 Black Hills match round. All 3 mic'd in at 1.55" ... .08" under the SAAMI minimum. The MAL round is very accurate out of my POF (16"), while the Black Hills (in 168 and 175) not as good. Also, fired MAL cases shows no carbon fouling on the outer case neck wall whereas there is considerably more on Black Hills'.

I assumed that since the BH was a true .308 it would have a bit more headspace slack than the SA & MAL NATO rounds, and would explain the difference in the amount of fouling on the case neck walls. But, to my surprise, they both had the same shorter headspace according to the gage (measured off the shoulder datum). Am I missing something? Could it be just the difference in powder that's causing the fouling variance?

Last edited by brmfan; July 23, 2010 at 10:20 PM.
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