What kind of quality are you looking for and what period correctness. Velvet or velveteen for an 1800's Colt or Smith, wool for a English or European case or felt for a cheap modern production gun. I use a high quality wool for mine try Muellers Billiards but ask for samples first, some of the cloth is really nice and others are really cheap looking and felling. Wool is more expensive but more durable and will not pill up and snag like felt.