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