im pretty sure you are asking about "boxer" primers. this means that the primers are for use in boxer primed cases. a case with a single hole for the primer blast to flow into the case. Berdan primed cases have 2 holes for the primer blast to travel thru. berdan primed case cannot be easily reloaded, whereas boxer primed cases are simple as pie
most cases in the USA are boxer primed even though the guy that designed that method was english and vice versa for Europe most are berdan primed though the guy that designed those was american.

propmahn
save the world, reload your brass