Cracked necks on loaded ammo

Years ago when I started building the 338 edge, I bought 100 pcs of once fired 300 rum brass. I worked up a very mild load to break in the barrel and get all the brass matched to my chamber. 60 rounds were placed in styrofoam blocks that come with factory ammo. The other 40 were stored in plastic shell holders for factory ammo. This was 10 years ago. I finished the build a few weeks ago and finally got around to shooting it this weekend. The first 60 rounds came from the styrofoam. All had some tarnish on them so I wiped them down real good. I had no issues with these. I then get the last 40 stored in plastic. The first one I started to wipe and the bullet pushed right into the case. The neck cracked all the way down the shoulder. I usually inspect all of my reloads but this was 10 years ago so i cant remember if I did. Pick up the second round and same thing, cracked. I started looking closer and could see cracks in several cases. Not all were cracked all the way up the neck. Some had a small crack at the neck/shoulder junction so the bullet still felt firmly seated. On these I was able to push the bullet to the side and split the case wide open. Out of the 40 rounds, I found 25 had cracked. On the remaining 15 I pushed on the cases with no visible cracks. I did this under a magnifying lamp. I tumbled the first 60 rounds I shot and inspected them very closely. Not a single crack.

These were all stored on the same shelf side by side. All loaded at the same time. The only difference is the styofoam vs plastic. Has anyone heard of anything like this?

Here are some of the cracked cases
http://i1335.photobucket.com/albums/...smaumrrps.jpeg


Sample of fired cases
http://i1335.photobucket.com/albums/...sxrvpex4x.jpeg

I just fired one of the rounds that passed my visual inspection and did not crack. Guess I will be pulling these and tossing the brass.

http://i1335.photobucket.com/albums/...pswrepi2hz.jpg

That I should strange. In for interesting topic.

It is strange. I am able to chip the brass away with my thumbnail on some of the cases.

The Brass was overworked without annealing. Causes could be from reusing the brass 5 plus times without annealing along with using a die that worked the neck to an extreme undersized condition (-.006 or more) for instance before pulling the sizing ball back through.

That was my thought too. Now explain why the first 60 rounds did not have a single crack in them. The cases were all tumbled when I got them, randomly picked up out of a container and loaded. What are the odds that I picked out the only 60 pieces and put them in a styrofoam block then put the 26 bad cases in the plastic. If it wasn't a safety issue I would shoot the 14 I have left to see if they all split. A couple were so bad that the bullet fell out of the case. I would have noticed this when seating.

I reread your post and I am wondering if you are experiencing Season Cracking. I honestly have no experience with that round so if there is an issue that is specific I am of no use.

Were the 60 mild load cases formed from 300 Ultra mag by you? That is a big jump in size. If they were not annealed after resizing that could be your problem. The splitting when you pushed the bullet in means the cases were hard. Without knowing the brass history and the quality of the anneal weather it was factory or otherwise, in my mind is suspect.

Good luck with your project.

I am not aware of plastic ammo cases causing this issue. Were there any other chemicals involved?

Ive had new Weatherby cases in the original boxes that were sitting on a shelf for a few years develop neck splits.
Also brass that gets reformed seems more prone to develop splits.
I don't have an answer, but im thinking that annealing brass before use or storing it is probably a good move.
Fact is though these type guns are hard on brass so get used to it. I only average 3 or 4 shots before I chuck my brass on a few guns.
Once the novelty of owning and shooting it wears down a bit, the brass will last considerably longer.

All 100 rounds were resized by me and loaded at the same time. There is no doubt these cases should have been annealed but at the time I knew nothing of it. I do anneal all my rifle cases now. I started reloading with my dad when I was a kid. Been doing it 35 years now. Other than rimfire and a couple oddballs, I have not bought factory ammo in this time. I have made thousands of 7.7 jap cases out of 30-06 and never annealed them till recently. Never had a problem with necks splitting.

To me everything is pointing to work hardened by use or by use of chemicals to clean brass. Annealing is your best friend. I purchased a box of 100 brand new nosler cases for one of my 6.5s and wouldn't you know it, I had a case neck split during bullet press. Pist me off because I paid good money for that brass. Recently purchased brand new, sealed box of lapua brass and guess what?.....that brass was annealed.

I heard a strangely similar story on another forum. Since I had several cases in each of my rifle calibers that were once fired bought online I decided to anneal all of my rifle brass over a period of time. Now reading this if any of my rifle brass is on the shelf for a while I'll anneal before reloading it.
Thanks for the share.

OP-

Were the necks in your second picture of your first post turned? If so, what was the final thickness of the neck after turning?

As some plastics deteriorate they give off ammonia based gasses. We all know that ammonia is one thing that can make brass brittle.
I use plastic shell cases and never thought too much about this. Never have they sat for 10 years. But often 1 year or more.
Research says that deteriorating plastic often has an ammonia smell. Guess I have never made a point to "sniff" old plastic. But there may be something to this.
I know I have reformed & reloaded 30-06 fired LC brass from the 1960s into 257 Bob A.I. Then reloaded it 10 or more times without annealing. I still have some. And oops, it is now stored in plastic!
There may be something to this. I don't know but sure would like to. Dad shot antique 30-30 brass that was over 50 years old but stored in "egg carton" style cardboard shell boxes.
Food for thought,
Randy

Wetherby brass is packaged in cardboard boxes, and as stated ive had new but older unfired brass develop splits while sitting.
Over the last 5 years or so ive also (inherited) several hundred rounds of modified Wetherby 378 brass and also several hundred of 300.
Some had only been fire formed and sorted for weight, and all were in the original boxes. It really wasent worth my time to sort thru it all, at least 90% got chucked for various reasons. I also received 3 full boxes of 20 each new unfired 300 wby necked down to 6.5 and I ended up chucking all of them after resizing up to 7mm. I did not anneal them before doing so, and splits developed after they sat for awhile. With large capacity modified cases its best to use new or once fired brass for hunting long range, after that use it for practice.