Case necks cracking


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dennisH87
February 3, 2008, 01:30 PM
My problem is about 1 in 5 case necks are cracking in my .22-250. I'm not loading them extremely hot or anything. 39.6 gr. H380 and a 40gr. V-Max bullet. I fired these cases once then have neck sized them since. They probably have 1-2 reloads on them allready. its a vertical crack about the length of the neck. They also have a very dark sute like coating on the outside of the necks. I sent about 20 of them back to winchester and they decided that it wasnt my fault, that i had a bad lot or somthing, but i'm pretty sure these arent from the same lot as the others. They ended up giving me 100 unprimed virgin brass for compansation. But does anyone know what would cuase this? I seems to me that the necks are getting work hardened too quickly and cracking. but from what?

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mc223
February 3, 2008, 01:51 PM
You did not mention what you are using to neck size. I would assume a standard die. Due to variances in chamber dimensions you may be working the cases pretty hard. Also crimping can have a detrimental effect on the working of the brass.
You may want to get a good chamber measurement and look into bushing type sizing dies.

rcmodel
February 3, 2008, 02:08 PM
22-250 cases have about a .001" thicker neck when new then say, the .223 Rem. case.
They also tend to thicken more, much quicker, from repeated shooting & resizing.

When I was shooting a lot of 22-250 years ago, I found it necessary to neck-ream & anneal my cases more often then anything else I have ever reloaded for.

It is also possible you have tolerance stacking in your rifle & die set.
A "maximum" chamber and a "minimum" die will quickly work-harden the necks.

If you continue to have problems, try at least annealing some and see if that doesn't cure the sooting and cracking problems.

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rcmodel

Idano
February 3, 2008, 04:02 PM
Dennis,

The first thing I would look at is the trim length; your chamber may be a little on the short side. Back in the 70's I had a new model 70 in 222 that split the brass, even new brass, and it turned out to be a short chamber. If you have access to a chamber gauge measure it and verify that it is longer then your trim length. I shoot a lot 22-250 in a 700 ADL and sill reloading the original brass I bought with the gun 15 years ago, but I have never turned the necks or annealed either. Since I only have one 22-250 I only neck resize anymore simply because I am lazy and don't like to lube the cases.

SlamFire1
February 3, 2008, 07:30 PM
Most probably you have huge chamber throats, and the brass is being overworked during sizing.

I am going to toss something out, chance of being right .01%. Bad powder.

I have had two batches of surplus 4895 go back in the case. No idea how old the stuff was, at least 20 years. Caused case neck cracks in ammo that had been loaded for a year. Brass loaded with the stuff had a 90% crack rate on firing. Pulled bullets and found corrosion on the bottom of some.

You would think that bad powder has a funny smell, well not at the start. It took five years for the first lot to turn red and smell bitterly acridic, but the second lot, had that faint ether smell, and no red.

Both were poured out on the lawn, in time.

So, how old is your powder?

dennisH87
February 4, 2008, 04:17 AM
I used a neck sizing die to resize the necks. I have used a throat demensions gauge if you will, and the throats way longer then the cases. i dont remember the deminsions, but the cases shouldnt ever get that long. I thought about anealing my cases from now on, but I've never done it before and dont have the stuff right now. My powder is fine. Its probably a year old at most. i bought it and loaded the cases right after i got the pound of powder. also, i dont crimp my bullets into place. idk, i might just end up sending these cases back to winchester and have them give me another lot of band new brass. This is becoming very frustrating. I shot 10 rounds and about 4 of them cracked. i inspected each one before fireing and after firing. it doesnt seem to do it on my hornady brass though. I only had one crack that was hornady, and it was its about 6th time loading. I have around 150 bulllets that i loaded last fall, all the same as the ones that are cracking, so those are probably going to all crack too.

stubbicatt
February 4, 2008, 09:10 AM
This is a mystery to be sure. Sounds to me like your brass may be defective. You don't polish using Brasso or any such stuff, do you?

Strange that it happens to all of them like that.

SlamFire1
February 4, 2008, 11:53 AM
You don't polish using Brasso or

Good point. Exposure to ammonia compounds cause "season cracking" in brass.

Millwright
February 4, 2008, 07:04 PM
Dennis,

I reload and shoot the .22/250 a lot but haven't seen your problem. Suggest a chamber cast with cerrosafe to get some dimensions. You may well be overworking your cases, causing brittleness.

For all new brass - regardless of mfg - I prep the primer pockets and flash holes, size and then neck turn the O.D. The objective is to get a loaded round neck dia just .0015-.002" less than chamber dia. If I neck sized only I expect I'd get even more rounds/case. I use RCBS dies for this and clean them often.

FWIW metallurgists I used to work with noted brass will 'flow' under the pressures commonly encountered in a rifle cartridge, and that flow is toward the case mouth. Same happens when resizing. All that working makes brass brittle and subject to cracking, so annealing is a good tool to combat it. Also check your case mouths; they should be smooth and even. Any nicks or sharp edges are source of potential 'stress cracks' . >MW

I only 'bump' the shoulder when I resize and have some cases with 8 loadings logged.

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