Hi David,
When buying from G-A or from another auction site where you do not know the seller, you might consider using an escrow service.
The trick would be to find one close to your home so you can inspect the gun during the 3-day inspection period. This assumes the seller has offered the inspection period, as well.
There was a gun shop near my home that used to provide this service for around $ 150 but he gave up his escrow license about 1.5 years ago.
But regular escrow companies may provide such a service...if they are not spooked about handling a gun in their office and can securely store one.
https://www.escrow.com/index.asp?PID=