Within every centerfire primer is a group of subcomponents assembled to exceptionally precise tolerances. Primer cup dimensions are controlled to four decimal places. The priming mix is specially formulated for consistent ignition with a wide variety of powder types, and tested for reliability. A unique tripod anvil design creates a larger "sweet spot" with maximum sensitivity - even with off-center firing pin strikes. This primer is compatible with small pistol calibers like .9mm, .38 Special, .380 ACP and many more.