APMEX volume is insignificant compared to COMEX. APMEX is also buying from and selling to individuals who are behing the world market. Finally, I've notice that APMEX doesn't seem to have the amount of silver eagles on hand as before. Under "availabilty", they simply say "now".
APMEX does have 100oz silver bars available. Plus you can buy physical silver right now via Sprott Silver trust in Canada. It is a physical silver trust. Eric Sprott who runs it does not screw around
Last I read shares were 15% above premium. So lets say an oz of silver there costs you 40$ right now