just curious. I am considering re-chambering my 458 win mag to a .458 cartridge which would have lower pressures. which of the 458 cartridges runs at the lowest pressure? how about the 458 lott? how about going to the 460 weatherby and loading lighter?

Using EQUAL amounts of the SAME powder, the larger case would run at the lowest pressures.

As a corollary, a .458 Lott loaded to .458 Win. Mag. velocity would run at lower pressure; a .460Wby. run at .458 Lott velocity would run at lower pressures.

Examine the reloading manuals for the specific pressures of reduced loads.

George