Weapon readily found round Lake (5)
I believe the answer is:
rifle
'weapon' is the definition.
(rifle is a kind of weapon)
'readily found round lake' is the wordplay.
'readily' becomes 'rife' (I can't explain this - if you can you should believe this answer much more).
'found round' means one lot of letters goes inside another.
'lake' becomes 'L' (geographical abbreviation).
'rife' placed around 'l' is 'RIFLE'.
Can you help me to learn more?
(Other definitions for rifle that I've seen before include "Firearm - plunder" , "strip bare?" , "Security provider with stock" , "One that has stock" , "Root" .)