Parts regularly given to a stalwart old spear-carrier (6)
I believe the answer is:
atlatl
'parts' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'regularly given to a stalwart old spear-carrier' is the wordplay.
'regularly given' means one should take alternating letters.
'old spear carrier' becomes 'l' (I can't explain this - if you can you should believe this answer much more).
'a'+'stalwart'='astalwart'
The alternate letters of 'astalwart' are 'atlat'.
'atlat'+'l'='ATLATL'
Can you help me to learn more?
(Other definitions for atlatl that I've seen before include "Throwing-stick" , "Stick in America" , "Would one have thrown" .)