This is a ten shot group after shooting and cleaning every 5 rounds with 400 grit diamond polishing paste until in cleaned up well.. This was after 20 rounds of previous slugs fired. While my barrel is not a Krieger or Benchmark, Broughton ,ect. It is much more consistent without a super rough bore with tooling marks. I might need to get a custom sizing die to.511 cast my slugs that are .513 and try that. Previously 3 shots groups were hard to obtain from a perfectly clean bore.