The most common and most likely answer to this crossword clue is the 8 letter word CONATION
C
O
N
A
T
I
O
N
Buddy explains!
The straight part
We know that "This leads to firm action" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case this leads to firm action = conation.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CONATION mean?
CONATION noun- The power or act which directs or impels to effort of any kind, whether muscular or psychical.