Can i resize 458 winchester once fired brass in a 458lott die set if its going to be shot in a 458Lott?Or do i need to resize in a 458winchester die set instead?Also will 375H&H brass resize into 458 lott brass by simply running in the resizer or is there more to this operation?Any help appreciated These rounds are new to me for reloading and i have both brass458wm& 458Lott... but only a 458lott die set right now......do i also need 458win.mag die set to shoot the 458 brass in the 458Lott rifle?I got boo-coos 375H&H brass i can resize to 458 lott if this is a easy to do project...

"Can i resize 458 winchester once fired brass in a 458lott die"

This is not from personal experience so, take it for what it's worth. The Lott is, of course, longer than the .458 Win but the final neck diameter is the same. I think you will find that the .458 Win cases are not sized down enough to give ample friction to hold the bullet firmly and you sure can't crimp the Win with a Lott die.

"will 375H&H brass resize into 458 lott brass by simply running in the resizer"

Certainly you can but might experience some split necks, especially if they have been fired and/or reloaded a number of times. If I were going to do it, I would anneal the cases first and then neck them up in stages. There are expander dies available that have multiple steps on the expander ball to do this. An easier way would be to use about 15-18 grs. of Unique with a corn meal filler on top of that and a tissue paper wad to hold the corn meal in the case and fire form them (NO BULLET). Again, unless you anneal them first, you will probably experience some split necks.

Thanks