Spill beans about large weapon (5)
I believe the answer is:
sling
'weapon' is the definition.
(I have seen 'Simple weapon' mean 'sling' so perhaps 'weapon' could also mean 'sling')
'spill beans about large' is the wordplay.
'spill beans' becomes 'sing' (I can't justify this - if you can you should believe this answer much more).
'about' indicates putting letters inside.
'large' becomes 'l'.
'sing' placed around 'l' is 'SLING'.
Can you help me to learn more?
(Other definitions for sling that I've seen before include "Support bandage; drink" , "ballistic weapon" , "harness for broken arm" , "Arm support; hurl" , "Simple weapon; throw" .)