If assembled with a casing, the casing 4 usually extends from {HEAD ~ the handle} 1 to have a good overlap over one end of the barrel 3, preferably to around {TAIL ~ the midpoint} of the barrel 3 and a capsule like cap 14 fits over the other end of the barrel 2 as shown in FIGS 2A and 2C 
If assembled with a casing , the casing 4 usually extends from { HEAD ~ the handle } 1 to have a good overlap over one end of the barrel 3 , preferably to around { TAIL ~ the midpoint } of the barrel 3 and a capsule like cap 14 fits over the other end of the barrel 2 as shown in FIGS 2A and 2C
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH