I'm resizing some new Nosler 30-06 brass to 8mm and I'm having a problem with the expanded necks. One side of the neck rim is higher than the other. I prepared the inside of the cases with a little lube, and the expanding process does not appear to require too much pressure. I've had to trim these cases back to make them uniform. It also doesn’t appear that the necks are thicker on one side than the other. I’m using an RCBS FL sizing die for this. I'm not sure what I'm doing wrong here. Any help will be appreciated.

I've had to trim these cases back to make them uniform. It also doesn’t appear that the necks are thicker on one side than the other.

That being the case, I'd load and shoot them once. Then pay particular attention to the necks after your next resizing operation. If you see a problem with the necks give RCBS a call. They might want to evaluate your die set?

Cheezywan

Try annealing every fifth firing. Sometimes new brass is crooked a bit and that's what a trimmer is for. Annealing brings fire hardened case necks back to dead soft and helps keep them from splitting down the road. It's easy to do, just stand your cases up in a shallow pan of water about a half inch deep and using a propane torch heat the necks just red and tip them over in the pan. Cheesywan gave you good adice.

Thanks for the feedback. I'll keep an eye on these cases to see how they look after the next resizing operation.

It sounds like you are trying to expand the necks using a regular expander ball on your full length sizing die. While the cases will work, and will clean up after firing and trimming, they are not pretty and raise doubts about where some of that brass went.

Can you post a picture illustrating the perceived problem?

I resized a new set of Nosler cases and this time adjusted the expander ball higher in the die (closer to the top). By doing this I hoped to have the newly expanded neck start to enter the upper portion of the die to support it while the remainder of the neck expands. This appears to help. I even tried this on some of the cases that were lopsided and they straightened out to be almost straight.

I did contact RCBS and they too said I may not be using a tapered expander ball for this die. I searched and found what I believe is a picture of a standard expander ball for dies and I have one very similar. I ordered a tapered expander ball assembly from Huntington’s and this should help.

Thanks for all the suggestions.

I have been reforming .30-06 brass into 8mm brass for many years. Take care...
Oberndorf

"...I'm having a problem with the expanded necks. One side of the neck rim is higher than the other."

What you are experiencing is common when expanding up, that's why I prefer to neck down if possible. Expanding up tends to stretch the thin/weak side and degrades neck concentricity. Necking down also works on the thin/weak side but tends fo increase the thickness there and that somewhat improves neck concentricity. No contest as to which method is superior, not to me anyway.

I have used bulk .35 Whelen brass (Rem, from Midway) to make .338/06 and 8 mm Mauser cases and use a Forster outside neck turner when, and if, necessary.

It is likely the necks are off-axis with the rest of the case and that the extra brass is coming from the shoulder on one side or the other. Sinclair sells a die body that holds neck turning mandrels so you can use them and their long taper for expanding necks. The inexpensive Lee sizing dies are extremely concentric and their long tapered expander might be just the ticket? With either tool, I would advise polishing the expanding portion by chucking it in a variable speed drill to turn it slowly against a spinning buffing wheel. You could also use a Dremel tool with small buffing wheel for polishing in lieu of having a proper buffer. Dico brand Stainless Steel buffing compound is just about perfect for polishing hardened carbon steel. I saw it at Harbor Freight last time I was in there.

After polishing, I would then treat the metal with MolyFusion to give it a permanently lubricated surface that will guard against other lubrication failure. If you aren't going to do that, I would at least get a bottle of STP at Wally World and pour a little into its cap and dip the case necks into it just before forming each one. You can do both, if you like? Soaking in mineral spirits will remove the STP.

It might be as simple as the '06 neck not being of uniform hardness around its circumferance, which is one of the common reason for necks being thicker on one side. Anneal the necks to dead soft, then expand them and see if the condition is better.

Bud W

I purchased a tapered expander/decap replacement assembly from Huntington for my RBCS FL die and resized another set of Nosler brass. This time the operation was flawless. Each case neck was uniform and even. The tapered expander ball is what I needed.