Peterson 40071I: 7mm Remington Magnum Long Brass Casings Bulk Box of 250rdsAll Peterson Cartridge cases are crafted from premium materials and precision-machined to exacting standards. Peterson 40071I Each case begins as a long coil of top-grade C260 brasscut into "cups" as the first step in the transformation process.These cups are then run through a draw press three times to elongate them into tubes. Afterward they are trimmed to length and thoroughly washed in preparation for forming. The rear of each tube is machined to create a primer pocket and an extraction groove.Next the case mouth is tapered to form the neck followed by another trimming to ensure precise length. A flash hole punches through the primer pocket and the neck and mouth receive an induction anneal-a critical step to ensure consistent neck tension and optimal bullet retention.