Bottle shown by two males seizing a loaded gun (6)
I believe the answer is:
magnum
'bottle' is the definition.
(I know that magnum is a type of wine bottle)
'two males seizing a loaded gun' is the wordplay.
'two males' means two replacements for 'male'.
'male' becomes 'm' (common abbreviation).
'male' becomes 'm' (common abbreviation).
'seizing' is an insertion indicator (inserted letters are seized).
'loaded' indicates an anagram (loaded can mean drunk).
'm'+'m'='mm'
'gun' anagrammed gives 'gnu'.
'a'+'gnu'='agnu'
'mm' going around 'agnu' is 'MAGNUM'.
'shown by' is the link.
(Other definitions for magnum that I've seen before include "Wine bottle twice normal size" , "Double-size wine bottle" , "Double bubbly" , "that may be full of slugs" , "Two champers bottles in one" .)