I got this TC from a friend and it was never been fired. I was using 50 cal sabot - Hodgdon Triple 7 FFG powder- cci #11 cap. The first two shots great. The third shot took two caps. The fourth took four caps. The fifth shot took five caps. I field clean it every shot. What should I do? I cleaned the gun when I got home a found nothing wrong. The nipple looks good.