I'm sure a number of you might be aware of this, but I'm posting it just as info for future reference to those who were unaware as I.
I was shipping a handgun today and decided to use a UPS Store thats local (I've used them before to ship parts--uppers, scopes etc.) I didn't have a box, so I got one and filled out the paperwork etc. (sending it to a FFL). Get the receipt, tracking number etc.
I leave. A little while later I get a phone call saying that they CANNOT ship guns.
I'm thinking why? Then I took a guess, and it was confirmed when I walked in and asked why. Since they are not DIRECT UPS employees (UPS stores are independent contractors) they have a legal issue. The guy at the store is pretty cool. He said he doesn't like it either and said he would be more than happy to have gun owners business in shipping.
Long story short I went to the USPS and got it sent out. Just wanted to let others know that if you use a "contractor" type of shipping service this could happen.

You shipped it Via USPS?
I didn't know you were an FFL..

What sixguns said. FFL required for shipping UPS unless it is direct to the manufacturer/dealer. All others use FedEx Overnight. Need a FedEx hub, not a Kinko's store type franchise, also. I'll never ship a handgun again due to it being such a PITA. Longarms in the US PO are easy though.