Fossilized bullets? Cigarette butts? Nope… belemnites.
In this case they’re Jurassic (~150 Ma) from the base of the Redwater member of the Stump Formation in the Red Wash area of Dinosaur National Monument, Utah.
And that’s about the sum total of my knowledge of these critters. If an enterprising paleontologist wants to elaborate they are invited to do so in the comments.