Jordan you seem to have a specific thing in mind and that is what club to use while practising a full swing. The club of choice in my view would be the 6 iron because it falls into the middle of the iron set. It is neither a short iron nor a long iron but actually is the shortest iron that requires a full swing. By practising with the 6 iron you will develop a full swing that is neither too long nor too short and one that will work very well throughout your set. Good luck with developing a great swing.
