Does anyone know of a cast bullet sizer in .412 for the .405 that is compatible with an RCBS lubamatic II? Looks like RCBS' custom shop (where I got other odd sizes) is defunct, that's not a standard RCBS size, nor does Lyman appear to offer one. The closest I can see is .410 and I think that's going to create some leading.

look around. There was a 413 one out for a spell from lyman. I have 1 but I'm not sure how many were made

My 405 slugs 0.412 and I use a custom 0.414 sizer. I had a guy on the Castboolits website make it and several others for me. Pricing was very reasonable and can’t fault the quality or service.