Greg, assuming you refer to the 30BR, it's a .330" neck diameter, and a ZERO free bore with a 1.75 degree throat angle(3.5 Deg. included). According to the prints, all of my other thirty caliber reamers feature  0.010"  free bore length x diameters of .3085" with 1.5 dgeree throat angles (3.0 Deg. included). In theory, the 13/4 Deg. throat angle is ideal for a 7 ogive bullet - I can't say I'm good enough to tell the difference; the 1.75 Deg. seems to work well with either seven, or 10 ogive bullets. . . and so do the 1.5 Deg. throats.

In my opinion, the ZERO free bore is perfect for 7/8 ogive bullets based upon the .925" long jacket, or the BIB ten ogive bullets which are based upon the 1.00" long jacket (118/125 Gr.) - it was for these bullets that the ZERO free bore was chosen. Worth note: going for a free bore of up to 0.050" offers more [bullet-maker] choices, while ZERO freebore may require a committment to an extra degree of specialization.

 Using my 112 Gr. bullet (7 ogive based upon the .925" jacket) with zero free bore and 13/4 Deg. throat, and the bullet just touching the lands, the base of the seated bullet rests just at the center of the [30BR] case neck. Ditto for the 118/125 Gr. ten ogive bullets (1.00" long jacket). Due to the longer shank section, opting for the seven ogive versions [of the latter two bullets] places the bullet base a little over 3/4 of the way down the neck - some find this undesirable - I do not like it because it hogs valuable case capacity! ;)  When set-up for a "just touches" condition, a free bore of the 0.050" variety results in about .080" of the bullet shank in the case neck - not likely to fail either (this is how my HV barrel is throated). I do not see the need for a free bore in excess of .050" in length.

Happy Holidays! R.G.