"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."  (copied from Bing search).  Even if you 'read into it', it doesn't mention anything about the size of the magazine.  At one time 15 round clips for semi-auto pistols were banned but are back now.  Limiting the size of the mag isn't going to make a difference.  Get a 5 round clip, practice and practice, and you're going to be very proficient with it making it almost as good as a 30 rd. banana clip.  Some where, some how, someone will find a loop hole in the law.  Have a nice/safe weekend.