Sorry Kirby, I'm with the Ranger on this one. I own a 7 Weatherby and my brother owns a 7 Rem. His best load can not match my best load. You are right by looking at the cases and saying that the case cap of the Rem "should" beat the Weatherby. But, I think the double radius shoulder has something to do with its performance. I met a guy at the range that had a 300 Weatherby that he rebarrelled with a custom reamer that mimicked the original 300 Weatherby except that he had angled shoulders instead of radius. He lost 300 fps at the muzzle with every load he shot.
But, the Dakota is faster than both. Too bad Dakota brass will cost as much as the rifle.
I thought about a 7 Dakota for a while, but decided my 7mm build will be a 7-300 Weatherby. It should be even with or slightly outperform the Dakota. Reamers, brass and dies are readily available.