On the one hand--all the cool dudes say it isn't illegal to own an AR15.
But when a new gun owner actually tries to get himself an AR he gets accused of being a pain-in-the-ass customer or a gun-control Apparatchik.
Do all you cool guys (who I've noticed won't actually actually TEACH a new gun owner anything, or help them get started--I guess unless maybe they happen to be queer) understand how difficult it is to actually find the lay of the land in Massachusetts? That most people have NO f*cking idea how to do a transfer--or the etiquette involved?
Maybe use THAT as a starting point when responding to a thread.
So all that being said, OP--here is a link to the NES Classifieds. There are dealers there who will sell you an AR lower, as long as you hold the appropriate license.
Dealer Classifieds
KAG Arms and Ma**h*** Firearms are all stand-up dudes with excellent reputations.
Or you could browse all the local shops within a comforable driving distance and see if they have any AR lowers for sale in their cases. They'd probably be happy to do your transfer for a $50 fee. You could ask.
Good luck--and if you want actual information, you should be warned (and would probably have already noticed) that this is the wrong 2A circle-jerk.