The most common and most likely answer to this crossword clue is the 7 letter word MEGATON
I've seen this crossword clue in The Times
M
E
G
A
T
O
N
More clues leading to the result MEGATON
- Soldiers around got upset with a bomb unit
- Measure of bomb, weapon with gas transported by soldiers
- Something without sparkle sent back with great force
- Not a stone to raise – big weight
- It’s not a stone to be lifted — it’s a heavy weight
- Huge weight, as opposed to a stone, raised
- Description exposing fake jewel put up for quite a few pounds
- Bomb unit, say, boarding coaster – OK?
- Middle Eastern gun on this bomb
- Large quantity of food packaging ending in recycling, with no return
Buddy explains!

The straight part
We know that "bomb unit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bomb unit = megaton.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 MEGATON mean?
MEGATON noun- A measure of the strength of an explosion or a bomb based on how many million tons of TNT would be needed to produce the same energy.