magazine capacity in Ma?

Does anyone know if a 15rd magazine in The Commiwealth is allowed if one posses a Class A LTC -no restrictions- ??

as far as i know the max is 10 rds. however if the mag was in this state and own by someone here prior to 10/21/98 it is ok no matter what the capacity.
some other strange stuff is all semi autos in this state must have a loaded chamber indicator, a mag disconnect and a ten pound trigger pull

Thanks. The law is confusing (go figure). I have a "large capacity" LTC, but I cannot possess a large capacity mag unless it is pre '98?!?!?! Gotta love the Libs!!!......NOT!