Re: 300 stw
It goes by many names, 30-8mm Rem Mag, 30 Super, 30 STW, 300 STW. Also almost every reamer is designed by the builder and will vary from gunsmith to gunsmith.
It is basically an 8mm Rem Mag necked down to what ever, 30, 7mm, 6,5mm.
Also some are "improved", less body taper with 30, 35, or 40 degree shoulder.
I have one that I use for 1,000 yd paper punching.