Not sure if the knock would work. I am sure they would work while your pulling back as the string at that point is perpendicular to the barrel. But once it is on th latch and you relax your hands the string pulls down in a V shape so I would think the knocks would need to be out a little since the string when in the V shape would actually be longer across the barrel, if not I think the knocks would pop up over the edge of the barrel. Does this make sense or did I confuse you more?