45″ barrel ” MS ” on the top at the breech.   Early 1795 Springfield type 1 lock.   Later arsenal parts such as the trigger guard, bands, and buttplate with is dated “1812”.   Full length walnut stock that appears to be an in-state mfg. also marked  “MS” on the left flat.  The state of Massachusetts purchased many surplus parts at the end of the War of 1812 and assembled and constructed these muskets due to the extreme shortage of available or serviceable weapons.   In very fine original condition.   An in-depth history of these muskets can be found in “AMERICAN MILITARY SHOULDER ARMS, VOL II ” by George Moeller.