Board Thread:Warhammer 40k General Discussion/@comment-33101051-20180809072443/@comment-27144409-20180821232836

Maybe if the skull was from an ogryn, orc or astartes, but those all seem fairly unlikely.

You could strap a pair of ripper pistols to a normal sized servo-skull, but then the mechanicus would have a fit about modifications, regardless of how useful they are.