It is my understanding that .458 Win can be fired in a 458 Lott chamber. Though I don't believe it is recommended for a steady diet as such. A .357 Mag will develop severe fouling in the chamber just ahead of the case if a lot of 38 Specials are fired through it. Making it harder to chamber the longer round, I would expect the same would happen in a 458 Lott chamber.

As far as the .375 Wby to a .375 H&H that is a no go because the Wby is an "improved" H&H with less taper and a double radius shoulder. You could rebarrel that rifle and have it chambered for the H&H round but if you have a 375 Weatherby you are getting higher velocity than the H&H round and I bet you could down load the Weatherby to H&H velocities cheaper than you could rebarrel the gun. Sean

I am thinking of making a 458lott, from the 458win, I am aware of possible magazine size problems. So once the conversion is done how interchangeable are the two cartridges? I have often fired 38spl. in a 357mag handgun,as well as 22shorts in a 22lr, no problems to date. I guess the larger case has me feeling a bit skeptical, as I don't want to ruin a good rifle. I also would like any info on a 375wby to 375h&h conversion as to feeding, pressure and are they interchangeable? All help will be greatly appreciated. thanks Ben(rug)

Thanks guys, I have no one here to coach me on large rifles . George , you are correct ,I had the conversion backwards on the 375. Ben (rug)

You should allso be able to fire 375H&H rounds in a 375 wheatherby chamber in the same way you can shoot an 243win in an 243 acley improved chamber. The fireformed 375 H&H case will be an 375 Weatherby case after firing.