As a CAS shooter, you are likely to acquire an old gun that perhaps was made over 100 years ago. Let us be aware, that as great as these old guns were and are, that we can not really document what ever got pushed through them, or what abuse they may have suffered. Get a qualified gunsmith, no not some other guy you know, I mean a qualified gunsmith. Someone who is paid for his knowledge and experience. Don' t be foolish.
Someone blows up a gun every day.
Don't you be the next. Some of the older guns can be loaded with black powder for which they were designed and continue to be fired in a safe manner. Measuring Tools To my mind, the most important tools after a good press and the loading dies. Simply, if you can not measure it correctly, it may not work. Buy the best you can.