I had the same issues with W-W primers being a bit undersized. I bought a brick and right from the start, I noticed they were falling into the pockets a bit too easy for my liking. I deprimed the live primers and substituted CCI's and Rem and the pockets were nice and tight. The mic showed that they were indeed smaller. I contacted Winchester and the lady I talked to sent me a shipping label and I returned them. In return, they sent me a voucher for a purchase of WW products. These were LR primers. I dont know if the other sizes had this problem but since that time I have pretty much been a CCI guy except when Obama was in office and then I found whatever I could. No misfires with any brand.