Will I be chared sales tax on my order?

Can an air gun be shipped to my address? Can I change/add to my order after it has been submitted? Can orders be shipped outside of the USA? How can I tell if an item is out of stock? How will my order be shipped? Is EliteForceAirsoft.com secure to order from? The drop out magazine of my BB pistol will not drop free. The rechargeable battery for my Airsoft Gun gets hot. Where do I send a gun for service? Which credit cards are accepted?