Why do necks split for some reloaders?

[gamestalker]

I see a number of reloaders annealing their necks because they are dealing with constant neck splitting or neck tension issues. And anyone who knows me, knows that I load em hot with slow burning powders., yet I honestly can't ever recall a single neck splitting in 30 or so years. I usually get from 12-15 reloadings off my belted magnum brass, and considerably more from standard bottle necks, and I don't think I've ever actually had a revolver case fail, and rarely will my AL pistol brass fail in less than 20 reloadings.
I don't think I do anything different than most, I keep my brass all trimmed to spec., properely formed, but I don't by any means ever load powder puff targe loads. I have two styles of loading for everything, hot and hotter.

 

[jmorris]

If you haven't seen a split case in 30 years of shooting you must only shoot water guns.

 

[243winxb]

Just had some PMC 223 that split necks really bad. All but 6 out of 100 were scrap by the 3th loading. Bad brass, not normal.

 

[FROGO207]

Some things that contribute to split necks IMHO are------

Over expanding/crimping necks, either one or both together.

Dirty dies that are galled/scratched can scratch the neck and cause weak spots.

Expander button scratched/galled causing problem as above.

Necks not soft/annealed enough and then have become brittle. Or poor brass to begin with

Using brass that has been degraded by ammonia/black powder or the substitutes. Or has been corroded in some way.

There are others I am sure but these are the ones that I find that are common and most on here have at least seen happen.

 

[gamestalker]

I pay close attention to certain details, keeping my dies clean, brass well groomed such as trimmed to same lengths, reamed and chamfered, and with bottle necks I always clean the inside of the mouths with a Q tip before seating. My bottle necks will always fail just above the web, but not until at least a dozen reloadings, and even longer for non belted one's.
For my straight walled brass, I don't bell the mouths, ever. I think this has a lot to do with why those never split. I ream, and then chamfer just enough for the bullet to start without shaving or tipping. I'm pretty picky about the mouths. When I load magnum wheel gun brass, it does require a full and firm roll crimp for obvious reasons. But still when my brass fails, it is never at the mouth and usually a primer pocket that gets to far out of spec. that qualifies it for the recycle bin. I know I'm one of very few that doesn't bell their mouths for handgun straight walled brass, but I'm beginning to think this is a primary reason I don't experience split mouths?

 

[Strongbad]

For me neck splitting is more common in my small bores. My 243's, 22-250, etc. Even then it depends on the brass. My 243's get fed cheap brass, whereas the 22-250 gets good Norma stuff. I've probably got 10 reloads through most of the 22-250 brass and I have a few splits, maybe 10%? I haven't kept exact count but the 243 brass seems to last about half that long. It wouldn't be an issue if I annealed them but for me atleast with the 22-250 I just use that as an excuse to go ahead and cull those and I'll buy new ones soon enough. Basically, for those rounds it's not worth my trouble. For my big stuff like 300 H&H, 338/378, etc. those usually get out of spec somewhere else OR they get annealed so split necks don't become an issue.

Otherwise, the last time I had a split neck on something big was a 300 Win Mag and that was years back. I also split a case on a 500 S&W a couple of years ago, but I also figure that case probably had 10 reloads on it, so it had it coming.

 

[cfullgraf]

I get a few neck splits in my commercially made cases, but not what I consider excessive. I lose more cases for other reasons before their neck splits.

The only exception for me are formed 6.5x54 Kurz Mauser cases. Case splits are more common and frequently are related to the cases I use for the parent case. I have not yet spent time working out an efficient method of annealing and that may help. I do not shoot the rifle that much s it really is not an issue. Cases are easy to form, best from 7x57 Mauser brass, but I have made them from 7mm-08 and 308 Wincester as well.

 

[TNBilly]

Just had some PMC 223 that split necks really bad. All but 6 out of 100 were scrap by the 3th loading. Bad brass, not normal.

I've had a variety of failures with PMC brass also though mostly web failures on the 2nd to3rd firing.

 

[EddieNFL]

Most of my split necks happen with brass I've necked up. I occasionally get one with cases fired in 5.56 chambers. Usually happens after six or so loadings. I'm too lazy to anneal.

I've had straight walled cases crack at the sides while the mouth was still intact.

 

[Fall Guy]

I think FROGO207 has it right. I had problems with split necks a while back and I thought it was britttle brass and needed to be annealed. I thought I just had a real bad lot of brass since it hadn't been overused. I eventually figured out that the expander in my Lee die was galled/scratched. I fixed that problem and the split necks pretty much went away from the remainder of that lot of brass. I can't remember if I had any more or not, but certainly nothing like I was experiencing.

 

[LoonWulf]

Ill have to check my 7mm die. My brass life went from 4-10 firings down too 2 or 3 with my most recent batch of win brass (which has always been good for me before this). I had thought it was just a poor batch...and one i need to streach as i cant afford to replace it.

 

[gamestalker]

I don't load for an auto loading .223, but I can certainly see where an AL cartridge of that operating pressure range would be more susecptable to wear and tear in general.