I have a buddy in MA who has a permit to carry.  He has a Gen 2 Glock 20.  I may have a deal here in TN on Gen 2 Glock 23.  Part of the deal is a 9 mm threaded barrel.

Is the 9 mm threaded barrel allowed in MA?

Good to go.

It does not violate any part of the AWB since the magazine inserts “inside” the grip.

I’d still recommend contacting whichever FFL you’re using in MA and give them a heads up. Tell them it’s a gen 2 and have the serial number ready just in case the want to confirm for themself.

Steve is materially mistaken on a portion of that.

A threaded barrel is one restricted feature under the Mass AWB, but that wouldn't preclude purchase / sale / transfer - the red line is two features.

You're going to have a bitch of a time getting one of Gaston's finest into Mass.  They were specifically, politically targeted in 1998.  Entirely legal for you to conduct the transaction via an FFL, but it may be a dog and pony show trying to get an FFL willing.

Ok let me rephrase. Here is the AWB regarding handguns.

Semi-automatic pistols with detachable magazines and two or more of the following:

* Magazine that attaches outside the pistol grip
* Threaded barrel to attach barrel extender, flash suppressor,
handgrip, or silencer
* Barrel shroud that can be used as a hand-hold
* Unloaded weight of 50 oz (1.4 kg) or more
* A semi-automatic version of an automatic firearm

I’ve yet to meet a dealer who will not transfer a gen 2 Glock. But I stand by my recommendation of talking to the FFL first.

Same here. Every FFL I have used for mine has transferred the Gen 2's no questions asked.  Sound advice though on talking to the FFL ahead of time.