I tried to record a video in LB2 of the impact effects that I was talking about, but the sim plays up nowadays and won't let Fraps work on my PC when it is running. I also tried to take some screenshots but that didn't work either.
I did, however, find ONE shot that I had taken previously which shows, to some extent, what I was talking about. Sorry it is just a single picture, and there's no motion to the animations to give you a better idea.
Longbow 2 30mm chaingun impacts - on the left is a 'hit' on the armor, on the right is a 'miss' on the ground just beside target.As you can see, there are two different impact effects for the 30mm, at least, depending on if the ground is hit or the armor is hit.