Best Starline Brass 6mm ARC Small Rifle Primer.  Starline Brass prides itself on producing the highest quality brass case available. Their brass is comprised of 70% copper and 30% zinc and is vertically drawn during the manufacturing process which results in more uniform wall thickness.

Brass Preparation: With bulk rifle brass you may sometimes notice a few case mouths are “out of round” or slightly dented below the shoulder.  With all new rifle brass, you should first straighten out the case and case mouth. Then chamfer and debur the case mouth inside and out.  To straighten the case mouth. Run the case part way into the sizer die and let the expander ball straighten the brass.  To prevent the case neck from stretching, be sure to lubricate the case neck inside the case mouth.In the event a case becomes stuck.  Purchase a stuck case remover; don’t use pliers, screwdrivers or other common household tools which could damage your sizing die.