Firearm with disconnector operated by breech bolt lock, and other improvements

Claim 1

A FIREARM COMPRISING A FRAME; A BARREL; A BARREL EXTENSION EXTENDING REARWARDLY OF SAID BARREL AND FIXED TO SAID BARREL; A BOLT WITHIN SAID BARREL EXTENSION; A FIRING PIN SLIDABLY RECEIVED WITHIN SAID BOLT; A HAMMER PIVOTED ON SAID FRAME MOVABLE TO COCKED POSITION AND PIVOTABLE FOR ENGAGING SAID FIRING PIN; A FIRING SPRING MOUNTED ON SAID FRAME; A STIRRUP CONNECTING SAID FIRING SPRING TO SAID HAMMER; A SEAR FOR HOLDING SAID HAMMER COCKED; A TRIGGER BAR RELEASABLY ENGAGEABLE WITH SAID SEAR FOR MOVING SAID SEAR TO RELEASE SAID HAMMER; SAID BOLT HAVING A NOTCH FORMED IN ITS LOWER SURFACE; SAID BARREL EXTENSION HAVING AN APERTURE FORMED IN ITS PORTION BENEATH SAID BOLT; A BOLT LOCK POSITIONED IN SAID BARREL EXTENSION APER-