A fixed sort of charge made by soldiers (7)
I believe the answer is:
bayonet
'charge made by soldiers' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'a fixed sort' is the wordplay.
I cannot quite see how this works, but
'a' could be 'one' and 'one' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for bayonet that I've seen before include "Knife fixed to the end of a rifle" , "Blade fixed to a rifle" , "Type of light bulb fitting" , "one's attached to one's rifle - that's sort of fitting" , "Dagger attached to 26 Across" .)