When the breech block is in the locked position, {HEAD ~ a clearance} is provided between {TAIL ~ the locking surface} and the locking element on the side facing away from the barrel 
is provided between
When the breech block is in the locked position , { HEAD ~ a clearance } is provided between { TAIL ~ the locking surface } and the locking element on the side facing away from the barrel
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH