now, someone who has a ton of land and shoots on their own property, perhaps.
but a free shooting range? no. I help run a range...between the hours involved keeps things maintained, paperwork, and misc crap that just needs to get done, there's no way the doors would stay open without yearly dues.
dont be cheap. buy a membership at a local club and go enjoy yourself (you do realize that going to a range can introduce you to a lot of fun new people? hell, i've met some friends because of shooting i wouldnt give up for anything)
There is a sort of "Free" outdoor target range in the Martin Burns WMA in West Newbury / Newbury. A permit is required to use it but, the permit is free if you've got a valid Mass Hunting or Sporting License.
you can see if there are open to public events at some of the clubs local to you
Hanson rod and gun has open to the public small fee shooting events see web site for details hansonrodandgunclub.org
Sundays 22lr steel plate, CMP 1st sat and 3rd sunday 5 for targets
trap wednesday nights and sunday mornings