Nice shadow trooper double-A, you might wanna look for a stormie rifle at some point, but the German MG-34 holds up pretty well... the 34 was actually the basis for sandtrooper rifles...
actually, I think you are probably using a Medicom sandtrooper rifle, in which case, they are inaccurate because that is a pretty much unmodified MG-34...
although there is
this pic of a sandie with an unmodified one...
but this type of sandtrooper rifle seems most likely to be accurate... (or should I say...
Mos Eisley to be accurate? 
)
I just don't think WW2 weapons should have made it into the SW universe without modifications to be definitively "Star Wars-y"