Brass Problem

[track]

What I first noticed is that the brass has rust spots, followed by a donut at the base of the neck, and then, belt bulge above the head, which usually occurs with belted magnums. I believe that the cases required "full length" resizing (no bumping the shoulder). The necks require outside turning, to rid of the donut.

 

[Heddok]

This still isn’t going to explain the out of round by .002” on once fired brass.

Yes- I agree with you, he also has an oversize chamber. The round fired in an oversize chamber will out of round.

 

[Heddok]

First - thanks to all for trying to help, I appreciate it a great deal.

Clarification:
The ridge is indeed downward....as in: brass is thicker toward the rim.
The dies are RCBS 7x57 Rimmed dies, not regular 7x57.

I have determined this is happening during resizing, not in the chamber. I measured a loaded round, fired it and the dimension just ahead of the rim did not change at all. And the ring didn't appear.
I moved the die into an RCBS press instead and used shellholder. Tightened die right down and resized. The ring still appears, but not as prominant, and all the way round the case, not just one side. The brass will chamber.
I am surmising maybe this die is very tight around the bottom. Perhaps I should back the die out a little instead of tightening it....that will be next....

Glad you got it figured out. Now go and blow a 100 shots downrange from your beautiful new gun!!

 

[Dmay]

Glad you got it figured out. Now go and blow a 100 shots downrange from your beautiful new gun!!

Well, not quite that easy....

I pulled a couple that wouldn't chamber.......proved they still wouldn't chamber without a bullet.....then sized them in the RCBS press with die cranked right down. The ring is there, although not prominent, but they still don't chamber. I got rid of the expander in case I was pulling the shoulder forward when coming out of the die....but didn't help....still won't chamber.
I gotta calm down and think for a bit......

 

[Potashminer]

Is reasonably old trick to colour up the misbehaving brass with Jiffy Marker - then try to chamber - see where it rubs off - gives you clue what is wrong.

 

[fingers284]

Im thinking that your die barrel is chambered off-center to your press c/l (or the shell holder is). Should be simple to rule this out, just measure the thickness of the die base metal one side to the other at the thickest point in the ring on the brass.

 

[DANS40X]

Now, w/ pertinent info provided-

Cast the chamber
Annotate the dimensions

Annotate the dimensions of a virgin piece of brass
Annotate the dimensions of a fired piece of brass

Modify the F/L sizing die.

 

[Dmay]

Well thanks again guys.

I had done the Sharpie-coloring thing, but was concentrating on the bottom of the case where the problem appeared to be. Upon coloring the shoulder area of a case and trying to chamber , it looks like the problem is actually at the shoulder. Not sure how good these pics will show it....

So the issue must be in the rifle chamber, or in the die. Thanks DAN, you cut to the chase and I may cast the chamber.....I guess a guy could plug and cast the die as well.
I think I will table the project for now and order a new FL sizer die, then resize few of these which will not chamber now and see.....

 

[Heddok]

I see it now. In your photo you can see that the neck is not being sized down all the way to the neck shoulder junction.

The die is just not a good match to the chamber. It's probably more common but the issue doesn't come up with a bolt gun because you can cam these marginally over sized cases and force fit the little buggers, can't do that in a break open gun.

I went through something similar with my 470 NE double.

Considering the price of the gun and the rareity of components and reloading gear it's probably wise to just buy a different sizing die or maybe several from different manufacturers.

Let us know what happens when the the new die arrives

Brad

 

[Heddok]

If you don't mind modifying the cheapest element in the chain... take a belt sander to your shellholder and take .003" off it. They are hardened so not as easy as it sounds. You could do this by hand but be patient.

 

[Dmay]

I have considered sanding down the shell holder, or the die, and I may yet. But for now going to wait until a new die arrives and will continue the saga when it does.

Thanks again guys.

 

[Potashminer]

If you don't mind modifying the cheapest element in the chain... take a belt sander to your shellholder and take .003" off it. They are hardened so not as easy as it sounds. You could do this by hand but be patient.

On last pictures that OP showed - with the Jiffy Marker - needs much more than .003" to get rid of that donut shape - needs like .100" to gain? If that "donut" was caused when the sizing ball is withdrawn - that case neck needs thinning at the base part?

 

[ChiliDawg]

I would check that your using the correct shell holder and its alignment. Those marks would line up with the bottom of the stroke for your sizing die?

This is what I was thinking since the OP mentioned resizing. It looks as if the case holder was not aligned properly.

 

[6MT]

Darrell, I take it you’re using the Co-ax? So free float physics says there should be no issue there. It’s either your die or your chamber. Those marks on the shoulder from your sharpie test tell a story.

 

[thump_rrr]

If you don't mind modifying the cheapest element in the chain... take a belt sander to your shellholder and take .003" off it. They are hardened so not as easy as it sounds. You could do this by hand but be patient.

He is using a Forster Co-Ax which doesn’t use shell holders.
I also use a Forster Co-Ax press. On my 5.7x28 die I needed to remove 0.003” from the bottom of my Lee die to get it to size properly. I removed the 0.003” using a large sharpening stone and air file.