Well then,in the .510 caliber slot, there is always the 500A2....
Not a wildcat.... SAAMI certified....
a 460 Weatherby necked up to .510, most neverneed a replacement barrel.

If you are willing to single feed them, you can always load 50 BMG bullets on them.
Let's see, a huntable rifle weighing in at 12 pounds (lighter if you prefer), no muzzlebrake....



375 H&H, as classic as a 30-06, and a puppy dog to shoot.