What kind of behavior can I expect of my puppy from 12-16 weeks?

This is the age when puppies become more independent of their owners and are likely to venture off on their own. Puppies that have always come when called or stayed close to their owners will now ignore them, often running in the opposite direction. This period can last from several weeks to months. How you handle your puppy's refusal to come or stay with you will determine whether or not he will be trustworthy off leash. It is important to emphasize here that no puppy this young should ever be off leash except in a confinement area. Therefore, keep your puppy on leash when this period arises and keep him on leash until he readily returns to you or shows no inclination to leave you. The privilege of being off leash outside of a confined area, is reserved for dogs whose owners have trained them to the point where there is no potential for them to run and fail to obey to stop or come on command. Releasing an unleashed dog in an unconfined area that is not well trained off leash is irresponsible ownership and dangerous to your dog. Even well trained dogs can make mistakes or become distracted by something in the environment so that they do not respond to their owners' commands.

Even if your puppy appears less inclined to bolt, this does not mean that he is reliable off lead without more maturity and a lot more training which is obviously where we should come in!