pellet vs BB shot

pellet and BB shot both are nouns.

Word	Noun	Adjective	Verb	Adverb
pellet	Yes	No	No	No
BB shot	Yes	No	No	No

As nouns, BB shot is a hyponym of pellet; that is, BB shot is a word with a more specific, narrower meaning than pellet:

Other hyponyms of pellet include BB, bird shot, buckshot, duck shot, grape, grapeshot, ball, musket ball.

pellet (noun)	BB shot (noun)
a solid missile discharged from a firearm	a small pellet fired from an air rifle or BB gun
a small rounded mass of a substance