Hollow weapon, it getting loaded with first of pellets (6)
I believe the answer is:
armpit
'hollow' is the definition.
(I've seen this before)
'weapon it getting loaded with first of pellets' is the wordplay.
'weapon' becomes 'arm' (synonyms).
'getting loaded with' indicates anagramming the letters (loaded can mean drunk).
'first of pellets' becomes 'p' (1st letter of 'pellets').
'it' anagrammed with 'p' can make 'pit'.
'arm'+'pit'='ARMPIT'
(Other definitions for armpit that I've seen before include "Axillary cavity" , "(In anatomy) the axilla" , "Depression under an upper limb" , "A sort of hollow" , "Leave" .)