A full hollow ground blade will sound, to varying degrees, like when you scrape a knife over toast as you shave. A full wedge, apparently, is the silent killer of facial hair, mowing through it with utter contempt and in total silence ... unless you cut your ear off and squeal like a little girl, but I digress. The tugging could just as easily be your pre-shave prep (might want a little longer to let things soak properly) or the blade angle.