If you are not resident of Colorado you have to pay for the the gun and have it shipped to an FFL in Georgia because Georgia does not share a border with Colorado.
The contiguous border thing has been gone since the mid 80s.
It's legal for a non-resident to buy a LONG gun in another state as long as the sale is legal in BOTH states. I don't know of any such restrictions in either Georgia or Colorado, but that's what the buyer needs to determine. There's also a possibility that the Colorado dealer will be reluctant to do it, as he's probably not conversant with gun laws in Georgia.
Sure fire way around the issue is to ship the rifle to an FFL in Georgia.
