I am pretty sure the two knives have the same length blade. From what I can make out on the dog tag: 5" blade, 10.5" overall length. The difference is in the blade prophile. The TB has a deeper belly and, thus, a wider blade and larger choil. It also has the double dip spine of the FBM. From the pics on the Busse Combat museum site, it appears that the first half of the blade may have a false edge/swedge as well. I'm not sure about blade thickness but with a name like "Tank Buster" it seems like it should be appropriately beefy.

