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Bart B. · December 21, 2012, 05:23 PM

buckhorn_cortez, if you go through every round with a concentricity gage and tweak the bullets in the case until the round-to-round variation is under 0.001 - and you can see the difference in accuracy, you are probably the only person on this planet to do so with a .308 Win. cartridge.

And your worst groups with bullets having .002" to .003" runout would have to be no larger than 1/4 inch at 100 yards.

Nobody in the top levels of competitive shooting with the .308 Win. cartridge would suscribe to this premise.

Besides, if you're measuring bullet runout with the cartridge resting on the body right behind the shoulder for the gauge's front reference and the case body right in front of the extractor rim for the back reference, you are not measuring bullet runout relative to how the case neck and bullet aligns in the chamber. The case body right behind the shoulder ain't where the cartridge centers in the front of the chamber when it's fired.

December 21, 2012, 05:23 PM	#111
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	buckhorn_cortez, if you go through every round with a concentricity gage and tweak the bullets in the case until the round-to-round variation is under 0.001 - and you can see the difference in accuracy, you are probably the only person on this planet to do so with a .308 Win. cartridge. And your worst groups with bullets having .002" to .003" runout would have to be no larger than 1/4 inch at 100 yards. Nobody in the top levels of competitive shooting with the .308 Win. cartridge would suscribe to this premise. Besides, if you're measuring bullet runout with the cartridge resting on the body right behind the shoulder for the gauge's front reference and the case body right in front of the extractor rim for the back reference, you are not measuring bullet runout relative to how the case neck and bullet aligns in the chamber. The case body right behind the shoulder ain't where the cartridge centers in the front of the chamber when it's fired. Last edited by Bart B.; December 21, 2012 at 05:32 PM.