Alpha Munitions 6mm ARC Brass

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If the rims are thicker check to be sure your extractor grabs the rim properly in gas guns. Lapua brass has a slightly thicker rim and gave me issues extracting when I replaced my bolt. I found quite a few bolts that did not have the extractor pivot hole drilled close enough to the face of the bolt to give proper clearance between the face and extractor claw for the thicker rim.