You need a tighter full length sizing die - or a smaller expander button. It this is happening on factory cases including Kynoch, your die is oversize or the expander button is, or - the bullets are undersize or a combination of these things. You will have to sort that out.
The bullets should be tighter in the '06 brass due to the new neck being on the '06 case's shoulder.
If the problem is the expander button, you can easily reduce it's size by fitting the decapping rod into the jaws of an electric drill, held in a bench vice- poor man's lathe.
Use sand paper, backed by a file for reducing it's size. Having dial or electronic calipers would be a good method of measuring, or using a micrometer to check progress.
The expander button should be about .373 at max.

Woodleigh for 270RN & 235gr. I would imagine
Hornady 270RN's are out of production. they still make 270SP's
Speer makes 235gr. and 270 SPBT's.
Norma is pretty much the 300gr. Alaskan.