Measuring neck tension

[Bart B.]

Keep in mind the way you hold the rifle to your shoulder can cause the same velocity spread as a few to several pounds of bullet release force. It's not easy to discriminate the cause of some velocity spreads when several are part of the system.

Bullet release or pull force will be different a day (week?) or two after measuring it a few minutes after seating.

 

[Campbell]

@Bart B.

I have skip read your technical posts. (it's Self-Assessment season with the 31 January deadline looming, therefore time is not at a premium)

Am I correct in thinking that your advice/argument is to keep "neck tension" (slanguage) to the minimum?

Many thanks for your input!

 

[Bart B.]

@Bart B.Am I correct in thinking that your advice/argument is to keep "neck tension" (slanguage) to the minimum?

Many thanks for your input!

Heavens no, not the minimum. Just related to the task at hand. When the round is in a firing condition is what counts. That's after all bullet seating nuances are history.

 

[rhovee]

This may have already been discussed but I am starting to believe that pulling force is more about neck tension than seating. If you use dry neck line the bullets seat very easy. But if you try and pull them, or seat them further down a few weeks later it’s quite a bit harder. I have a loaded round of .295 and neck bushing is .294. Neck measures .2935 when coming out of the die. So I figure .0015 neck tension. Correct me if I am wrong. I am always wanting to learn more.

 

[Bart B.]

I have a loaded round of .295 and neck bushing is .294. Neck measures .2935 when coming out of the die. So I figure .0015 neck tension. Correct me if I am wrong.

I find it interesting the sized neck diameter is smaller than the bushing neck.

Shouldn't it be a bit larger due to springback?

 

[rhovee]

I would think the same thing. Not sure if annealing is making a difference. But it’s smaller. Still has a little seating force so I am not worried about to much. I have taken the measurement from lots of different pieces of brass.

 

[Bart B.]

To me, neck tension (interference fit) is the difference between bullet diameter and sized case mouth (inside neck) diameter. That eliminates any brass spring back issues.