What is the difference between interior and exterior moulding nails?

Hosey, the main difference between any interior and exterior nails is what the nail is made of and the ring shank for fastnening strength. Most exterior nails are made to resist rust and have a shank to accept wider ranges of swell and shrink of materials. Are you using the fasteners for wood, metal or vinyl? If you are installing exterior moulding, you should look into using adhesives in conjunction with nails.

Moulding nails??
If you mean finish nails, the difference would be that exterior would be galvanized and the interior would not (called bright). Exterior could be aluminum.