one shot vs unit of ammunition

one shot and unit of ammunition both are nouns.

Word	Noun	Adjective	Verb	Adverb
one shot	Yes	No	No	No
unit of ammunition	Yes	No	No	No

As nouns, one shot and unit of ammunition are synonyms defined as:

one shot and unit of ammunition: a charge of ammunition for a single shot

Other synonyms of one shot include round.

one shot (noun)	unit of ammunition (noun)
a charge of ammunition for a single shot	a charge of ammunition for a single shot