With Curl's logic all new 450/400's should be made with .408" bores. All that new ammo would shoot well in the new rifles and safely, if poorly, in the .411" rifles. The fellow with the .411" rifle needs to roll his own, but he'll have plenty of fresh brass to do it.

HopDoc,

Since the 450/400 3 1/4" uses the full lenth 450 3 1/4" case, but the shoulder is so far back, a new cartridge with a more forward shoulder would work. As an additional benefit, moving the shoulder forward would create more space in the case, enabling better ballistics with the same pressures. How much better, I don't know. But it would end up somewhere between the 450/400 3 1/4" and the 500/416, probably closer to the 450/400. I think its a great idea, and even better if it were to use the .423" bore of the 404J or .435" bore of the 425WR, but the market is a small one and as Capt Curl points out, pretty set on the century old but eminently successful cartridges.

JPK