The silvered weapons don't have any crazy effects because those characters already have the advantage of magic. If you want one of the silvered blades to shoot magical cutting-projectiles, it would be a result of your magic, not the weapon itself. Not that they don't have nifty hidden features themselves. Although maybe not as drastic as the sin ones. Your characters don't know any other spells at this point either, so the magic itself would have to be part of your 'Signature'. [s]I really need to come up with a better name for it...[/s]

Otherwise, you'd need to be strong enough to produce an air current powerful enough to cause that effect, which in MY universe is completely possible, but we won't go into that for now.