Cracked Cases

[CP]

Anyone have an idea what’s going on here?  Overpressure is the obvious answer but I’m below the Max recommended load.  Could it be something else?

[Bookworm]

Are there any signs of pressure on the bases. Just because the book says you are under max pressure doesn't mean you aren't.

[Ray]

Looks like old brass. Sometimes I get neck splits when using older brass. That's when I usually retire that batch/lot no. This almost looks like a variant of that. You may want to look for more stout brass too and consider reloading it less times.

Read this. http://www.firearmstalk.com/forums/showthread.php?t=2660

[demontang]

If that brass as been reloaded a few times it could just be the brass. My reloading book talks about the cases doing that after being reload to many times.

[300rum]

Are you using a full size die or are you neck sizing?  If you are full resizing you are probably overworking the brass.  I always had to use a full die when resizing belted mags and by doing this I only loaded them a couple of times because it works the brass quite a bit.

[Slenk]

Looks like they been loaded one to many times. Don't rely on books for max loads you need to work up loads for each gun. If you take a piece of wire and sharpen one end and then bend it in a L shape, you can check your brass inside for a indentation where yours are cracking . If you feel any indentation throw the brass out.
Slenk

[CP]

Thanks for the all replies, they are very informative. 

This lot of reloads is the 3rd firing (two reloadings) of mixed brass (Win, Rem & Fed).  All brass was full sized once and neck sized once.  There is some flatting of the primers but it is not excessive.  I checked all the cases with a wire as suggested and found a couple with internal cracks that haven’t gone all the way through yet. 

All the cracked cases are Winchester; there are no cracks in any of the Federal or Remington brass.  So it looks like I have a combination of over-pressure and weak brass.  I’m tossing all of this lot of brass and I’m going to retire this loading.  Which is a shame because I really like this load. 

[jeff100]

The brass in cartridge cases flows forwarded a bit with each cycle of shooting/reloading.  That's why cartridges become longer and eventually need trimmed.  That flowing forward causes the brass walls to thin near the base of the cartridge.  If pressure really isn't an issue, then this could be the cause of your failures.  Try new brass if you really like the load, and use a good quality brass.  If you're still suffering this type of failure with new brass, you might want to rethink your pressure analysis.

Hmmm.  Unless...could this be a headspace issue?  Belted magnums headspace the cartridge on the belt IIRC, not sure if that could be an issue here or not....might want to consult a competent gunsmith.

[Coasthunterjay]

it doesnt look like old brass.....

what dies are you using to reload?

what grain powder and type of powder are you using?

what caliber?

I think this is a head space issue maybe o maybe aseating problem with your dies.....but?

[Big10gauge]

Head seperation can be caused by excessive headspace, overworking your brass when resizing it, or the brass has just been reloaded too many times. It is one of the most common forms of brass failure and one of the first things you need to look for when reloading. Loading hot loads quickens the process. You might want to try neck sizing or backing your full sizing die out a little bit so it doesn't bump the shoulder back so far. I'd get your gun checked with some no-go go gauges for a starting point.

[MHWASH]

Big10 took the words out of my mouth.

[Ray]

It certainly could be a headspace issue. I would not rule it out. I lean towards overworked brass which creates thinned brass walls = old brass which needs retiring. If you buy or use a brand new lot of brass and the issue does not happen again it could be concluded. Maybe even a different load too. A high pressure load will wear our your brass faster than  lower pressured ones.

[jeff100]

When I looked at this post early this AM (after being up all night) I thought that brass was belted cases.  Now looking again, I don't see any belt, just deformation.  So I'd say this is either weak/worn out brass and/or still possibly a head space issue.  I'd have a gunsmith check the head space to be sure that's not an issue, and as I said before, try new quality brass...

[12Gauge]

It appears more like a combination of a oversize chamber and brass being loaded to many times.  Take it to a gun smith to be absolutely sure.  Using a neck sizer and only loading your brass a couple of times my cure the problem.

Look a the primer, is the primer seem to be coming out or protruding out? if so them it is more likely to be a head spacing issue.

[Slenk]

CP
If you are seating your bullets out to far and they are touching the rifling lands you will create alot more pressure. I have several rifles that I can not seat the bullets to book specs. And have to seat shorter.
Slenk