Guess I shouldn't of called them bird bangers, they are called cracker shells which is just about as confusing.
Here is an old link about what I'm looking for, some of the replies do know what I'm talking of, but for those who are curious.
https://www.farmshow.com/a_article.php?aid=9393
I had a few of these around a few years back, but the kid in me got the best of me and I used them as a fireworks display.