Is it one which has a minimum dimension set, and a tight neck, or a bit sloppier and able to handle all ammunition including the various Nato loadings?

Also, should the throating be short to allow for engaging the rifling, or long for pressure issues?

My persoanl choice is a .340 neck with a short enough to reach the lands throat, and a minimum body.

Trying to anticipate Cornerstones next quandry.................................

308sako
It really depends on what your use is. If it is a hunting piece no need for tight necks and having to turn necks down. On the other hand, a Hunter Benchrest(HBR) rifle you need a tight neck, min spec'd chamber.

If you only want to use a certain bullet and case, then having a reamer made may make sense.

My HBR is chambered for the 308 Obermeyer with a 0.333" neck. The leade is 0.068". This is a perfect match for bullet around 1.100" long and using Lapua 308 brass.

I agree with MSwickard, if you are going to shoot BR you'll need a tightneck reamer with min specs. Have the throat ground to accomodate the bullets you plan to use. If this is a hunting/informal target rifle PTG makes a fine 308 Bisley reamer that is perfect for most brands of Match 308 ammo. I build quite a few Police Sniper rifles and use the Bisley reamer.