Hello all, does anyone know of a manufacturer that makes rimless basic brass with a .588 - .590 head like a 416 Rigby or 338 Lapua magnum. Thanks for any information.

I've got 460 basic brass with a .580 base; you can turn the rims off easily.
Unmarked.

Thanks for the offer but that would be too much of a difference it size for me.

Norma used to sell the Rigby basic cylindrical which I turned into 470 & 500 Mbogo
before I got the proper headstamp.

Jamison, now Captech International, sold the Lapua basic cylindrical brass to me once upon a time.
I used that for my .510/.338 Lapua wildcat the .500 Bateleur.
You might give them a call and see if they are still doing it.