So here goes. I was going through some of my loaded ammo for my 6.5-06AI last night. I have not shot this rifle in a year or so because I have been playing with other projects. I noticed that in a large number of instances, like 3-4 out of 20, the necks of the loaded ammo had split while sitting on the shelf.

Let me explain how I load these. First, I use 270 brass. I use a Redding neck sizer to size it to 6.5, then I trim to max length for the 6.5-06. The reason for the max trim is because I know it will fit the chamber AND that some of that will pull back when I fireform.

To fireform, I load a 140 grain bullet with a medium high load of AA4350 so that the bullet seats into the lands and the cartridge is a slight crush fit into the chamber. Then I fire them at the range. Most of the time, this is fine. Occaisionally if I want a sharper shoulder, I will fire again. All looks good by this time.

For final loading, I simply neck size again and load the 120 Ballistic tip and go have fun.

Since they have only been fired once or twice, at the most, I have not annealed the cases yet. When I looked at the neck splits last night, it looked like someone had cut the necks straight as an arrow from case mouth all the way to the neck/shoulder junction. No partials and only one that appeared to look like it was just starting into the shoulder.

The other thing I noticed was that on some of the newly sized brass, it appeared that there was a shiny line from mouth to shoulder. I could not "feel" it with any of my picks on either the outside or inside on the neck, but it was there. This was the initial sizing. What I did not have time to do was take apart the sizing die to see if there was a flaw in it. I will do that tonight.

Here are my questions. Has anyone seen this before? Can it be because I am sizing the necks down and making them "too tight" for the bullets and they are just giving way after a time? Can the necks really need to be annealed after only one firing? Any other suggestions would be helpful!

Thanks.

I have had that happen with surplus 308 brass.I have anealed the necks and have not had that happen any more.It it a shock when you find them HUH.Good Luck

The phenomenon is called age-hardening and is sometimes seen even in new NOS (New Old Stock) ammo, especially some military stuff made during WW2. The cure and prevention is to anneal the brass neck/shoulder area about every 5-10 loadings or even more often, some BPCRS shooters anneal every time.
Regards, Joe

"Can the necks really need to be annealed after only one firing?"
Yep

Ive found that with some batches of brass I get cracks after once fired.
I would annel your brass before or right after you size it, then maybe again after once or twice fired
You might just have a bad batch
I just reloaded some ww 308 brass and found 2 cracked cases that were aneled just 2 loads prior, so I aneled them again.

You first reformed the necks, then fired it a few times. Now it's gotten stress cracks in storage. ??

Seems maybe you should have annealed immediately after the reforming step?

Thanks for the replies. Looks like I will take the advice and anneal immediately. I would not have expected it to happen after one firing, but such is life.

I had the same thing happen when 6.5X55 brass could not be found. I used new 30-06 brass and annealed it first, ran into a 250 die, then the 6.5 die, trimmed and outside neck turned them.
I annealed again when done.
They shot good and I only shot a few, the rest in the box were loaded but unfired. They sat for a year and when I went to shoot, all the necks were split.
Makes me wonder how a guy can make drastic case changes for a wildcat.
I make 7R brass from 30-30 cases and never had a single split neck.

I think the other thing I will try (again) is necking up 25-06 brass. I will lube it better as well to see if it helps.

Thanks for the thoughts!

Larry,
Just another thought but have you checked how much your resizing die is working the brass? This could contribute to the splits also.

Blacktailer, I thought about that. The expander button is sometimes hard to retract from the case, but it happens with both the regular full size die and the neck die. I was also just thinking I would just try it without the sizer button to see what happens.

If the expander is hard to extract it needs
lube. Use a Q-Tip and put a scosh of Imperial
Die wax on the inside shoulder neck location.
A very little bit goes a long way.
If you used a liquid brass cleaner it could
cause storage cracks also.
Good Luck!