We customarily cut slightly into the shoulder when neck turing in order to prevent a "doughnut" from forming in the inside neck wall. I have seen two reasons advanced for that: (1) to assure consistent neck tension and (2) if there's a doughnut it could restrict or impede the flow of gas up the neck.
Even with my simple layman's knowledge, point 1 makes sense to me -- we want to have consistent neck tension. But it seems to me that if the bullet is seated out far enough that the shank does not contact the neck/shoulder junction, then a doughnut would not be an issue as far as neck tension . . . unless I'm missing something here.
I'm curious, though, about point 2. Does a doughnut really have an effect on gas flow to the extent that it would show up either in terms of uniformity of velocity or the accuracy of the load? Or is it an old wives' tale?
Thank you,
Dave Rabin
Even with my simple layman's knowledge, point 1 makes sense to me -- we want to have consistent neck tension. But it seems to me that if the bullet is seated out far enough that the shank does not contact the neck/shoulder junction, then a doughnut would not be an issue as far as neck tension . . . unless I'm missing something here.
I'm curious, though, about point 2. Does a doughnut really have an effect on gas flow to the extent that it would show up either in terms of uniformity of velocity or the accuracy of the load? Or is it an old wives' tale?
Thank you,
Dave Rabin