I was loading up some 308's Third time in the press, full length resizing as these are fired in my single shot break action and the necks pulled right off!
Brass work hardend?
Not enough lube?
Too much lube? What do you think.

My guess is its LC brass and/or brass came in contact with ammonia or vinegar.

Key word: break-open. These actions are generally not considered optimum for high pressure rounds, and the 308W is well over 50K Psi IIRC.

I make it a practice to anneal my cases every other firing. They last forever.

Rich

Lee expander can be rough,polish them. When FLRSing, you can push the shoulder back to far. Case stretching can happen anywhere on the case, but most its near the head, sometimes in the middle of the body,or in the neck. In the neck i have seen 357sig have the neck pulled off using Lee dies, but this is a thin walled neck. Your brass is on the brittle side for some reason. If brass cleaned/washed in a chemical, you could have "Stress corrosion cracking" or "Dezincification" these conditions take a while for the Corrosion to start. If its LC brass, they do testing using a chemical to age the brass before firing, it is then sold as scrap. If you have some of the LC brass, it could be your problem also.

quote:

Brass work hardend?

That's my guess. Do you lube the inside of the necks with mica or other dry, inert lubricant? That'll reduce friction of the resizing ball.

-WSJ

I use the Lee water base white lube. I apply inside the neck with a Q-tip - no annoying SCREECH and little no steretch.

To remove lube, I boil my brass in water with a little dish soap for about 10 minutes for 15 minutes followed by rinsing with hot tap water. I usually spread them out on newspaper - if pressed for time, dry them on a cookie sheet at you lowest oven setting.

Thanks for the input guys. Just for the record they are rcbs dies and I use water based neck lube on a q tip. I am going to keep working on this problem. Mike

I bet those cases are Winchester brand!
I too have found this to occur on brass that is too hard in the necks, and if you have a standard sized expander button it makes the situation even worse!
You want to only expand your case necks just enough to hold a bullet firmly, around .0015"-.002" is plenty. Measure your expander ball with a micrometer, if it's more than .002" under bullet diameter then you need to polish it until it's .002" less than bullet diameter. This is my preferred maximum, but most rifles work well with .0015", which is my minimum.
Most dies overwork the brass considerably in the neck area, and hard/brittle brass only needs a little extra work to start to crack.

A far superior case neck lube is powdered graphite, a little on a case neck brush is all that's required, it will improve the sizing effort dramatically!

Due to this problem, I have switched to bushing style dies, either FL or NS depending on the cartridge and use intended. I no longer use expander balls in practically all of my reloading, and it has eliminated cracked necks.
I also anneal my brass after the 4th sizing.

416 Rigby pretty much nailed it. These cases are hard an need to be annealed. I would also agree that powdered graphite is a far better lubricant for the inside of case necks. A case neck brush or a Q-tip applys it nicely.If anyone has trouble finding graphite go to your local John Deere dealer.For a few dollars they sell you a lifetime supply.