Errr, depends on where you are.
For instance, Michigan has no state law against openly carrying firearms, so you should be free to sling one around the woods provided you're within DNR regulations.
On the other hand there's a strange distinction in our laws that says anything that can be fired in a configuration under 30" is a pistol, and you can carry a pistol concealed. This means an 870 w/ a 18.5" barrel and top folding stock is a pistol. Now, HOW you could conceal that is left as an exercise to the reader.
Laws are whacky, and as I said: It depends on where you are.
