Looking for load data for 458 Lott with 300-350 gr jacketed bullets

[ssj@ms.metrocast.net]

I would like to find some load data for 458 Lott with 300-350 gr jacketed bullets. Can I use existing/published data for 458 Win Mag?

[versifier]

Welcome to Gunloads ssj.

COTW says three things:
The Lott case, based on the .375 H&H, is .3" longer than the standard .458M case.
.458Mag ammo can be safely fired in a Lott chamber.
The cartridge was designed specifically to improve on .458 performance with a 500gr bullet for dangerous game.

I can find nothing in any of my manuals here with Lott data, but it is a proprietary design now controlled by ASquare, who sells brass & bullets for it. I would be contacting them first. Sierra doesn't make 500gr bullets, but it wouldn't hurt to contact their techs to hear what they have to say. They might be able to scare up some data for you or find a good source for it. You might also try the Reloaders Guide forum (the link is at the top of the page) and also this forum: www.reloadbench.com

While one might assume that using .458 data could be OK (like you can use .38spec in a .357M or .44spec in a .44M), I couldn't advise it and would never consider doing so myself without hearing from someone with actual experience with it. Life is to short to take unnecessary risks with the pressure levels of a cartridge that can spit out a 500gr bullet at 2300fps.

[ssj@ms.metrocast.net]

Much appreciated. This kind of info is hard to find.