BFD?

General Firearms Terminal Ballistic Information
1

So I must admit that I don’t fully understand this whole “Back Face Deformation” thing. My understanding is that it occurs when a round hits a plate, the back of it expands in the direction of travel of the round, and the blunt force trauma does damage to the wearer of the plate.

That said, I’ve heard some controversy on this one. I’ve heard some report that talking about BFD in armor plates is like talking about ft lbs of energy in rounds - it just don’t matter in the real world.

What is the truth on this subject?

2

The vast majority of the time, BFD is a non-issue, especially with plates worn over soft armor.

3

Thanks for the reply, Doc. I’ve got one other question:

What about with stand-alone plates and no soft armor backing? I’m assuming that it may come into play a little bit more, but it’s still not a huge issue?

4

It could be more of an issue, as can spall.