.38 caliber vs .38-calibre

.38 caliber and .38-calibre both are adjectives.

Word	Noun	Adjective	Verb	Adverb
.38 caliber	No	Yes	No	No
.38-calibre	No	Yes	No	No

As adjectives, .38 caliber and .38-calibre are synonyms defined as:

.38 caliber and .38-calibre: of or relating to the bore of a gun (or its ammunition) that measures thirty-eight hundredths of an inch in diameter

Other synonyms of .38 caliber include .38-caliber, .38 calibre.

.38 caliber (adjective)	.38-calibre (adjective)
of or relating to the bore of a gun (or its ammunition) that measures thirty-eight hundredths of an inch in diameter	of or relating to the bore of a gun (or its ammunition) that measures thirty-eight hundredths of an inch in diameter