Must have been. I just doubled checked moments ago and I killed a floater with an explosive shotgun along with a good chunk of the terrain.
Happy days

Now this gives me some ideas...
--- posts merge ---Hmm, unsure if it works properly/fully... seems that only one pellet is doing HE/Incendiary damage, the others -

I've killed someone with a single 4-pellet Incendiary shot so he must've received more than single dose of incendiary damage... However, these incendiary pellets destroyed some wooden walls as well (

)...