Red,
You are right. I haven't any experience with a 30/378 or the Warbird. I have had experience with a .300 weatherby vs a .308 win vs a 6.5x55 and I see no advantage at the ranges I shoot game animals. If I hit a deer or pronghorn with a bullet from any of these guns in the boiler the deer, or what ever, falls down within 40 yards. I have seen a deer shot with a .300 RUM at 200 yards and the deer went about 25 yards. About what I would expect if I had shot it with any other caliber. If you hunt at extreme ranges, which is your perogative, this is where these calibers shine. If someone wants to buy one, great. Keep the economy churning. I just don't see the advantage at normal ranges.

Dr Fatguy