So shall it be

St.^3 Jon of Needham say:

>Sturmplasmagewehr then?
>StGW?

Sounds good to me, for the RF anti-personnel version.

For the big point-target one, "Plasmafaust" sounds just right!

[Tomb:](Except you've already named that one an SK (SturmKanone) if I 
recall..... but Plasmafaust might well be a nickname for it). Anyway, 
we'll call the other one an StGW then.