When Peterson Cartridge decided to come out with its own .338 Lapua Mag casing we perceived that there was not a source of really good, match-grade, sniper quality .338 Lapua that was made in the US. We decided that if we were going to produce .338s, we wanted ours to be as good as or better than the best foreign-made .338 L M.

So we spent more than a year studying the casings of the best foreign manufacturers. We ran scores of tests on annealing temperatures to get the grain structure just right. SAAMI, the standards organization for our industry, specs outside dimensions of casings but there are no specs on internal dimensions. So we cut casings in half and studied the internal geometry of the best, to uncover their secrets, and where possible, improve on them. In our lab we have an electronic machine that measures the force required to insert a projectile into the case mouth what we call neck tension. This enabled us to ensure that our casings were optimal for bullet release. The end result is what we believe to be the most accurate shooting .338 Lapua Mag casings on the market.