Neck Tension?

[Pathfinder76]

What does everyone like for neck tension on your cases? I’m curious as to thoughts. It seems 0.001 to 0.003 is a consensus, but which one is all over the map.

[elkhunter11]

I like .0015" to .002".

[fps plus]

For neck tension I like Swedish massage

[260 Rem]

.002” for cartridges that are not tube fed.

[6MT]

For my precision bolt guns, it's more of a feel when seating. I don't neck turn (I don't believe in doing it). I do anneal every firing though. Consistency is what I seek. Neck sizing shoulder bump dies do the trick for all (except the BMG) rounds. Smooth as butter is what I seek. (And yes, they are firmly held by the neck.)

You certainly can tell the difference between virgin and fired brass when you seat.

[Bushrat]

According to several long research and testing articles full of formulas and equations in a study of metallurgy in relation to brass rifle cases in the now defunct Precision Shooting Magazine anything more than about .002-0025" pushes the brass beyond its elastic retention capabilities. If you neck size for .005 smaller than bullet diameter the bullet when seated in that brass will obviously resize/stretch the neck diameter of the brass to fit the bullet, if that bullet is pulled the brass will not spring back to .005 tension, it will only spring back about .001 - .0015 if that. Neck tension in reality can only equal the brasses capability to stretch and rebound. In most cases that is about .002" -.003" max for the most elastic brass. More like .0005 to .001. The inside neck diameter measurement after a seated bullet has been pulled is pretty much what your actual neck tension measurement actually may be. Not that neck tension can be measure in inches.

A bullet being seated into a neck that has been sized to give .005 neck tension gives more resistance when seating a bullet than one being seated into a neck that is only sized to give .002 neck tension, thing is the resistance you feel is not indicative of how much neck tension you are achieving, the seating resistance is coming from the bullet resizing and expanding the neck to accomodate the bullet but the neck tension when measured the proper way by how much pull force to remove it from the neck will generally not be much different than the bullet seated in a neck sized to give .002 neck tension.

Different brands of brass, different lots of the same brand, age, amount of work hardening, annealing, neck thickness, etc, all have effects on the ductile and elastic properties of brass. Measuring for neck tension is a rule of thumb kind of guestimate and is useful for consistency but won't give accurate readings of neck tension. That can only accurately be measured in pounds and ounces of tension required to pull a seated bullet from a neck. That requires specialized equipment most don't have so we are stuck with measuring inside neck dia. in relation to bullet dia. It seems the rule of thumb is .002" -.0025", any more than that and the law of diminishing returns comes into effect, we gain nothing except needlessly overworking our necks.

[Pathfinder76]

Interesting. Makes sense for sure.

[Cow Town Bill]

Originally Posted by chuck

What does everyone like for neck tension on your cases? I’m curious as to thoughts. It seems 0.001 to 0.003 is a consensus, but which one is all over the map.

I like about 2 thou. I've found that if I'm using common brass like Remington that the tension varies considerably because the brass neck thickness varies a lot. Problem disappears with Lapua brass. Could neck turn the Remington brass but that is time consuming. Better to bite the "bullet" and get good brass.

[303carbine]

Originally Posted by fps plus

For neck tension I like Swedish massage

You mean from Dolph Lundgren????

[fps plus]

Originally Posted by 303carbine

You mean from Dolph Lundgren????

In this day and age I'm not one to judge , if Dolph is your thing that's great( not that there is anything wrong with that as per Seinfeld ) I'm more into Hannah Graaf