well as best as i can tell you can only have 10 round mags. you have to have the stock pinned. an the muzzlebrake must be pinned. no threaded barrels, no bayonet lugs. kinda like NY used to be. also appears you need to have a license to purchase card or something.. but thats just how i understand it. im no lawyer nor a resident of mass... go to a LGS and ask them they should be able to give you solid info.
I have been a silent witness
to all of America's finest hours.
But my finest hour comes
when I am torn into strips and used as bandages
for my wounded comrades on the battlefield,
When I fly at half-mast to honor my soldiers,
Or when I lie in the trembling arms
of a grieving mother
at the graveside of her fallen son.