I've just been looking at the reloading pages and was wondering why the 458 Vincent short has higher velocity than the 458 Lott - 500grn bullet.
What is the case capacity of both?
Is this just a matter of higher pressure in the Vincent cartridges?

The Vincent is based on the improved 404 Jeff case, and even when held to COL 3.375 with a 500 grain bullet, it holds the same amount of powder as the 450 Ackley at COL 3.60 inches. This is enough to give an extra 100 fps over the Lott.

These days the equivalent of the Vincent short and long is probably better formed from the Lazzeroni case with the bigger .557 inch shoulder for better headspace control and either lower pressure or another 100 fps. The long version would simply be a 10.57 Meteor necked up .042 to .458 and should be a snap.

So the 458 Vincent is a fat bastard, that explains the speeds it achieves from a 30-06 length action.

Maybe Winchester will adopt the 458 Vincent Short case as a base for 338 and up Short Mags? I'm game. I could see that being a really handy 416 Short as well.

Thanks for opening my eyes to yet another possible cartridge (this and the other Vincent post).

Thanks for the reply Sabot

Gonzo
The 404Jeffery is the parent case for the Vincent also the Remington ultra mags and the 416 Dakota if I remember correctly.
So the 338Rem ultra mag and the 416Dakota are the full length versions already.

... and K Howell did a 2.5" Jeffery in most popular caloibers already. Good stuff.