First off.....WHAT THE FUCK!!!
Well, this would be kindof hard, because we cant just mod the image of the M9, because...well thats just the image, it might show up but the range...the "programing" is just the same...
and with a giant sword...if you hit them...wont you make a obvious mark on the wall? =.=
...why dont we just mod a good gun...(idk default M4A1) so it looks like a knife...