Neck Tension

[nettlle]

Never really had time to investigate neck tension but I am starting to research it now. I did some measuring today on my 308 reloads and they have .003" neck tension. I am reading that .003" neck tension is good? If one was to get involved in adjusting neck tension is there a die specifically for that? I.E. would there be a separate station for the neck tension die? Also are special mandrels required? These 308 reloads are for my M1A and part of the process is running them through a small base die so that they will chamber. Neck tension die after the small base die?

 

[Blue68f100]

If your running on a simi-auto (M1A) your good as is. I would not even think about reducing neck tension. A mandrel expander is what is used most of the time but there are other ways. Like not fully sizing the neck, to reducing the wall thickness of the necks.

Leave your as is for your M1A.

 

[PWC]

Neck tension is measured in pounds not inches, but I'm not going there.

What you mean is you have .003 difference in the case neck OD dimension from sized and no bullet, and sized with bullet seated. .003 is generally accepted as OK.

 

[243winxb]

A Redding Type S fl sizing die could be used with or without a mandrel expander die. The Redding allows use of an expander or no expander.

The .003" is good for your auto. The GI 5.56 minimum bullet pull is 35 pounds. This is about .002"

https://www.sierrabullets.com/reload-basics/reloading-for-semi-autos-and-service-rifles/

See Neck Tension.

 

[AJC1]

Neck tension is controlled with bushings or mandrels, coupled with neck turning. That rabbit hole is deep. 21st century sells mandrels in .0005

 

[FROGO207]

Neck tension is controlled with bushings or mandrels, coupled with neck turning. That rabbit hole is deep. 21st century sells mandrels in .0005

Add to the above that annealing the necks will even out random tension due to work hardening of the dies and firing of the brass.

What you are describing is amount of interference fit between bullet and neck. All the above is how to basically adjust for it.

 

[AJC1]

Add to the above that annealing the necks will even out random tension due to work hardening of the dies and firing of the brass.

What you are describing is amount of interference fit between bullet and neck. All the above is how to basically adjust for it.

I do appreciate a good machinist term. I don't know why loading needs is own lingo, but yes.