The most common and most likely answer to this crossword clue is the 7 letter word PETARDS
I've seen this crossword clue in The Daily Telegraph
P
E
T
A
R
D
S
More clues leading to the result PETARDS
Buddy explains!

The straight part
We know that "Explosive devices" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case explosive devices = petards.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 PETARDS mean?
PETARDS noun- A small, hat-shaped explosive device, used to breach a door or wall.
- Anything potentially explosive, in a non-literal sense.
- A loud firecracker.