It is possible to mail order the Remington 10s, the downside being that you have to pay an extra 25 dollars Hazmat shipping fee. But if you order a couple thousand caps from Cabellas, thats only about an extra 1.25 per tin. Or if you have a buddy to go in with you, you can split an order. That's what I ended up doing to get the Remingtons when I started shooting BP this past spring.
By great good luck, Cabellas is opening a new store here in Columbus Ohio next spring so I should be able to get my supplies there from now on.