Case neck split question

[Comrade Terry]

I've never seen a case neck split running laterally (parallel to the case mouth). The split is at the junction of the neck and shoulder.

This is a .308 Win case which has been fired 7 times, and was annealed after every firing. The necks are skim turned and bushing sized for a 0.002 'tension. The load is not hot (43.4 grains of N140).

What's going on here?

Photos:

 

[SHootSTraight22]

I've never seen a case neck split running laterally (parallel to the case mouth). The split is at the junction of the neck and shoulder.

This is a .308 Win case which has been fired 7 times, and was annealed after every firing. The necks are skim turned and bushing sized for a 0.002 'tension. The load is not hot (43.4 grains of N140).

What's going on here?

Photos:

Do you think you thinned that area out by removing the donut area?? Also, how far did you push the shoulder back while sizing??

 

[Comrade Terry]

Do you think you thinned that area out by removing the donut area?? Also, how far did you push the shoulder back while sizing??

That very well may be what's going on. I try to just kiss the shoulder when I turn the necks, but I may have gotten 'vigorous' on that one.

As far as bumping the shoulder - minimal. The shoulder rarely makes more than nominal contact with the die. Usually, only 2 or 3 cases of 100 have the shoulder bumped, and then it's on the order of 0.001 or less.

Thanks for your input.

 

[SHootSTraight22]

Do you think you thinned that area out by removing the donut area?? Also, how far did you push the shoulder back while sizing??

That very well may be what's going on. I try to just kiss the shoulder when I turn the necks, but I may have gotten 'vigorous' on that one.

As far as bumping the shoulder - minimal. The shoulder rarely makes more than nominal contact with the die. Usually, only 2 or 3 cases of 100 have the shoulder bumped, and then it's on the order of 0.001 or less.

Thanks for your input.

I asked that about the shoulders because I was wondering if even more stress was being placed there due to the case being "pulled there" under set back, plus the bushing pushing there??? Add to that it being "thinned out due to neck trimming," then that maybe it???