Weapons companies lug inside (8)
I believe the answer is:
firearms
'weapons' is the definition.
(firearm is a kind of weapon)
'companies lug inside' is the wordplay.
'companies' becomes 'firms' (I've seen this before).
'lug' becomes 'ear' (I've seen this before).
'inside' means one lot of letters goes inside another.
'firms' placed around 'ear' is 'FIREARMS'.
(Other definitions for firearms that I've seen before include "Weaponry" , "Weapons" , "Portable guns" , "they can kill people" , "Rifles, guns, pistols etc" .)