Let’s just say it: the crossed muskets front and center really make me think the name of this county is Bullet, but the flag designer misspelled it because he or she is from Kentucky. It’s not very nice of me to revert to a yokel stereotype, but I’m sure 90% of readers would agree. First impressions are a bitch.
Once we get past that, the symbolism is kinda janky. The white background represents salt, which was an important natural resource in Bullitt County 200 years ago. The green in the text represents the fertile land and prolific game from 200 years ago. The muskets represent the fact that 200 years ago, people shot other people a bunch to get their land. The 20 stars refer to Bullitt being the 20th county in Kentucky (in 1796, naturally.)