Split cases

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Split cases

Postby TacoTaco » Wed Feb 24, 2010 8:57 pm

So heres the deal- I worked up a load that my carbine seems to love: 38.0gr LiL Gun, Hornady once fired brass, CCI 400's, 250gr FTX, 2.235 COAL. Shoots .7-.9" groups routinely. Problem is, I seem to be splitting cases. Not badly, but I've noticed a small hairline fracture running about 3/4" of the length of the case on several cases. Anybody else have this issue? I picked up a couple of pounds of Win296 today, after hearing that its slightly slower burning and should help with pressure issues. Any advice would be appreciated. I've been reloading .223 and .308 for years now, but I'm new to the big bore stuff.
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Re: Split cases

Postby Mike » Wed Feb 24, 2010 9:09 pm

Now, I have zero experience reloaidng the 450, but annealing cases has always been a "stitch in time" when it comes to keeping brass around longer.

Is it splitting around the neck? I know it seems odd that once fired would split, but it does happen. If it was winchester stuff, Id send it back with case lot # and get a voucher for money off my next purchase, but, they arent makin 450 brass yet.
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Re: Split cases

Postby Siringo » Wed Feb 24, 2010 9:31 pm

TT -- splitting cases indeed would be very rare and odd with this caliber. Pressures are just not up there enough -- . Are you sure they go all the way thru the case wall or are they deep scratches. Can you take a pic and post it?

In fact, when I first starting shooting my rifle, I thought my cases were split too and traced my problem to my Bushmaster stainless steel Magazines which had very sharp lip edges. Upon feeding, the cases would have a cut about the length you were mentioning. Also is the possiblity of the case catching the edge of the locking lugs prior to chambering -- but I ruled that out.

I lightly polished the leading edges of the magazine feed lips by wrapping a piece of 400 grit sand paper (automotive) around the case, twirling it and the scratching went away. The cuts were pretty deep, but did not seem to effect the case life. I am still using them after 15 loadings. When I switched to modified magpuls -- no more scratching.

Regarding annealing -- I am not so sure this is a good idea. The 450B headspaces on the mouth of the case and softening it would lead to battering and shorting the case life. On another post, can't remember who observed this, but repeated firings caused the cases to get shorter. Kind of the opposite of a case with a shoulder.
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Re: Split cases

Postby TacoTaco » Wed Feb 24, 2010 11:55 pm

Hmm...now thats something I hadn't thought of. The mags could be scratching them. When viewed from the inside of the case, there is no crack or split visible. Maybe they are just scratched. I'm going tumble and size them to see whats what. The reason I thought they were cracked is because my fingernail was getting caught when rubbed across it. Either way, thanks for all the feedback guys, its appreciated!

BTW, anyone have any good recipes using Win296 and FTX's?
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Re: Split cases

Postby Siringo » Sun Mar 07, 2010 10:47 am

Here is a photo (blurry) of a case that had a very bad and deep scratch. Think it occurred early in the life of the 450 upper when the locking lugs had very sharp edges or from the magazine before I polished the feed lips. The case has cracked, but only in the area where the Lee Crimp was used. Any cases with deep gouges will eventually fail. Best to cull them.

Image
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