My red catty was ok for the first 100, peaked at 200 swings, and then didn't improve after that - lasted around 800 swings for me. Weird that yours got worse with more hits. That's only happened to me once with a JHM7120 RI - got hot, then sound changed (for the worse) and got loggish, and then broke once it got better again. It seemed like the bat go an internal crack which worsened performance and maybe that's what happened to yours.