Try to use a bayonet? (4)
I believe the answer is:
stab
This clue is a double definition.
'try' is the first definition.
(I know that stab is a type of try)
'use a bayonet?' is the second definition.
(I've seen this in another clue)
'to' acts as a link.
(Other definitions for stab that I've seen before include "Jab" , "Pierce with a knife" , "Impale; attempt" , "wound as Casca" , "Wound with a dagger" .)