Home Forums Reloading Big Game Rifles NON CONCENTRIC BRASSI I

I have some 7x57 brass that is not concentric in the neck area. How it got there is most likely resizing die not set up right. The question is what is the way to fix this brass or is it a throw away situation? Some has not even been loaded or fired yet. Some pieces were only out 1-1.5 Thousands and some were as much as 6+. I'm going to try full length resizing w/o expander button 1st. Maybe if I gain a little there and then try to fire form them in the rifle I might be able to save them. TIA
Have a great day.
Jim

I always adjust the expander button. Size one piece, check it m turn 1/8 turn resize, keep doing it until you see the smallest run out. I'd start with annealed brass

Try the sizing without the button. It's very likely the brass will be sized straight, but there are some bad die bodies out there.

There are several possible sources of neck runout when the expander ball is in place.

1. The neck walls of the case are not of even thickness all around. Even a well fitting and straight/true expander assembly won't do well with really bad brass.

2. The expander assembly has a problem.

3. The neck section of the die sizes the brass down so much that even a straight expander assembly and good brass won't produce straight sized cases because of the heavy work the ball has to do when coming back out of the case.


Do you have a means to measure the uniformity of the case necks?

Bad brass - perhaps

He said some has not even been loaded or fired yet. That would be an issue with the brass itself, and not the die set. Generally if the die is adjusted properly, and there is not a profound issue with the brass itself, you will load straight ammo. As you know.

I get by with regular ol RCBS dies, but they are adjusted properly. I also run the expander ball, as they were designed. Hopefully the OP can get this sorted out. If the brass is really bad, he may have to turn the necks??

I was also in the same boat a while back, when I bought some used brass for a 300 RSAUM. The brass I bought from someone here was not concentric at all, and the batch I bought from a guy on gun broker was pretty straight. Sometimes you get bad brass and have to deal with it. If the neck thickness is such/inconsistent that it can not be corrected, it gets tossed..

I was dealing with the highlighted portion.

Fireform the brass, then set-up your die properly next time.

You will have a much better chance of getting straight brass if you use Mule Deer's trick of running the expander as a separate step. Also the problem of non concentric brass has been discussed here quite a bit and IME if it is less than about .005 it doesn't make much difference. YMMV.

I do not have a good way to measure neck thickness. The batch of new brass was Norma. I always chamfer new brass inside and out the full length resize. Thanks for replies. I'm going to take the button out and resize to see if they improve. For a normal hunting rifle what is a tolerable amount of runout. A 200 yd shot would be max in my hunting area and most likely 99% would be under that. 30 - 60 yds is the norm as I'm a woods hunter.
Have a great day.
Jim

I've not found 0.006" to be detrimental.

Sounds like the last batch of Winchester 7x57 I bought.

Complete garbage.

I wouldn't run them through a full length die. I'd use this...
https://www.brownells.com/reloading/case-cleaning-prep/case-neck-turning/tin-mandrel-kit/