Peterson Brass 6mm XC Small Primer *The flip top cases are considered protective packaging and cannot be replaced if cracked during shipment. Box of 50 Made in the U.S.A. Peterson has been producing top quality match grade brass for years now. Peterson is always expanding the line of brass that they produce and this is one of them. Creedmoor Sports will carry Peterson 6mm XC SRP brass as soon as it is available.