Im loading 12.5 gains. 250 grain Lead bullet. Using CCI 300 LP. Im getting un-burned powder flakes. Had this issue with 10mm before using winchester primers. CCI mag primers took care of the issue. And i since loaded 10mm with CCI 300. And it burnt fine. Im concerned with trying the magnum primers for the 45 colt though. Gun im loading for a is an SW 25-5. 8 3/8 inch barrel. So i can't bump it up to much to get more pressure. Tips ideas? Thanks.