So, this .475-338 Lapua monster. Original idea was to put on a Mauser at 3.34" COL, but it's damn near impossible to justify putting all of that work into a VZ or take-yer-pik, when you can buy a M70 in 270 used for $400 and come out way on top.
And with Ed poisoning my mind with thoughts of third recoil lugs, I took a sec to redesign my "first child" to a little longer COL.
I figure that Lap brass, if blown out intead of expanded, just might make .2690" or so. Even is a bit less, no matter.
I have a case body 2.240" long, .5730" at shoulder (my notion of min taper), 35* shoulder, and .40" neck.
With a 3.53" COL I find the same capacity under a 2.27" Swift 500g as the 460 Weatherby!
Of course I wouldn't load a M70 to the same pressure as a Weatherby, but I'm feeling pretty confident about the 2500 fps mark. Especially with this "third recoil lug."

Then there's the ubiquitous question of "why," the wildcatter's bane. For one, I love the M70. There's lots of aftermarket stock choices, magazine/bottom/small parts upgrades available, and they are everywhere; I think the safety is the best. For two, the Lapua brass is tuff stuff, and about the same price as Rigby. For three, one might get away with a bit less recoil than, say, the Mbogo (one of my all-time favorite 'cats, mimd you) b/c of less powder used. For four, when chasing after the 470, there's really no cheap way to go, so you're not actually tossing money for nothing (like some of my other 'cat ideas!) I got no five, but give me time, I'll see what I can do!
When it was going to be stuffed in a K98, I called it the 12mm Maus. Now that it's a bit bigger, and since much of the imspiration and design rides on the coattails of the 470 Mbogo, I think I have to call it the 475 Mdogo (kid/calf/youth? Who speaks Swahili here?).
Hope Dave doesn't mind!

[And John, I promise to give much more lead time on this one!]