Need advice. World does not want to sell me 257 Roberts brass. I have a small supply of 8 mm Mauser brass. No 8mm guns nor do I want one. After lubeing with an RCBS lube pad I ran three pieces through a 7mm resizing di. Lots of dents in the shoulders. Ran one case through a 257 di. No more dents just what the 7mm di put in it. I can probably eliminate the dents when I blow the shoulder out,m but I would prefer not to have the dents to begin with. Brass is R-P that i got at a gun show several years ago and is at least once fired but shiney. I have several dies that I could use to resize the neck before I go to the 7 mm. 30-32 are available. I would welcome any and all suggestions to prevent the shoulder dents.