Character whose clumsiness with guns is a running joke in The Pickwick Papers (9,6)

'character whose clumsiness' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'with guns is a running joke in the pickwick papers' is the wordplay.
I cannot quite see how this works, but
'with' could be 'w' (abbreviation) and 'w' is present in the answer.
'a' could be 'an' and 'an' is found within the answer.
'in' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
This explanation may well be incorrect...

Can you help me to learn more?