Many dealers on gunbroker also sell on ebay. They won't mind if you switch. If you want ebay to feel it, stop buying any sporting goods from them. E-mail the sellers and let them know what you are doing. When their sales dry up, so will ebay's fees they charge on each transaction.

When Wal-Mart started discontinuing guns, I stopped buying sporting goods from them. I won't even buy a license from them.