Bullet bras are often described as “not working” for smaller busts, but that’s not really accurate. The issue is usually that the structure of the cup isn’t being fully supported, so the silhouette doesn’t hold as intended.
Historically, padded bullet bras already existed to address this. The purpose wasn’t to create cleavage, but to support the cut and stitching so the shape remained consistent under clothing.

It’s the same design logic, just adapted for different requirements, which is why choosing the right construction makes all the difference.

https://www.whatkatiedid.com/products/padded-bullet-bra