Bolt for safety mechanism on guns when at boiling point? (2,2,4)
I believe the answer is:
up in arms
'bolt for safety' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'mechanism on guns when at boiling point?' is the wordplay.
I cannot quite see how this works, but
'mechanism' could be 'pin' (pin is a kind of mechanism) and 'pin' is found within the answer.
'point?' could be 's' (S is an example) and 's' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for up in arms that I've seen before include "Protesting vigorously, in militant mood" , "Rioting" , "Young child may be found here" , "Better prepared for battle" , "Outraged" .)