Split necks - Grendel

After shooting a hog this evening, I put the brass back in the MTM case, but noticed that one case had a split neck. I examined the other fired cases and found that 14 were split and only one was not. These are Hornady cases (I think twice fired previously) and have not been annealed. Over the years I’ve used a lot of different brass, but never Hornady. Is short case life the usual, or maybe my barrel chamber is out of spec?

This is the new (used) 6.5 Grendel upper. Ballistics Advantage barrel.

I have read of people getting 10 plus loads from Hornady brass, most I have loaded any Hornady is 5 so far. I did anneal after 3 shots though.

The Grendels lower pressure SAAMI Max is about 52,000psi IIRC and most published data is around 50k psi.

I messed up on quoting this one and edited. Sorry Gasguzzler somehow lost your post.

You are correct 50 K is very high compared to many cartridges handgun and rifle alike no doubt. I should have been much more detailed with my thoughts on that post.


But compare 50K to some of the other modern rifle cartridges it is many run at 60K and some at 65K so it is considerably lower than those.

Bill Alexander the man behind the Grendel said you would have no issues other than shorter case life running the Grendel at 58k in a boltaction rifle.

I have loaded cases 5 times without any issues without annealing and that seems to be common with this cartridge.

Kmon11

With all but 1 split I’d say you have a chamber problem.

Check what your fired brass measures outside diameter then size it and check it. Could be your die versus your particular chamber‘s neck is causing an over worked situation.
I have ran into that on Peterson brass that I know is good brass but one of my 22Creedmoor dies sizes .003 more in the neck than the other so if I use it with a rifle that has a looser neck the brass may only go 3 firing unless I anneal.

After mentioning the split necks and wondering why, and if it’s a chamber problem, I realized I had 2 Grendel ARs. The grandson’s is in the safe. If I fire some rounds in each rifle and only get split necks from mine, then it has to be a chamber issue. I got the upper for a good price. Maybe that’s why the good price.

Anyway, I’ll post what I find.

I have seen Hornady 22-250 ammo split the neck on one firing.

Point being, they do make some brass that is brittle on the case necks.

Maybe, had you annealed it after the first firing you would have had zero split necks.

The next step I would take, before worrying about chamber or dies, is to anneal some more once fired brass, size and load it and see if it splits the necks again. As is the case with so much in hand loading, when trying to correct a problem or develop a load for a firearm, only change one parameter at a time.

If the brass was twice fired previously, that means this firing was #3 when they split. I know from experience case mouths need to be annealed after the second firing (sometimes the first firing, depending on the caliber) if you plan to prolong case life. The answer is to anneal your case mouths. You are experiencing normal wear on brass that has been loaded multiple times and not annealed. Case necks will get work hardened and become brittle, then crack after firing or when sizing. I HIGHLY doubt something is wrong with the chamber. If you think it's the chamber, measure the fired cases at the neck and see how much expansion you get. Also, AR's are much harder on brass than a bolt gun is.

Also, Hornady brass has not been the best quality. It's softer, like the Federal brass is. I generally see the Hornady brass wear out in the primer pocket first, when using a large rifle primer. The Grendel is a small rifle primer pocket, which helps prolong the life of the primer pocket, since there's more "meat" around the primer pocket at the case head.

It isn’t the chamber. I took some of those reloads and fired them in the grandson’s Grendel (Odin Works) and got the same split necks. It has to be the brass. And some of those neck splits were also cracked at the junction of the neck and shoulder. No case head issues.

And next I fired some factory Hornady 123 gr SST ammo in both Grendels and had no neck splits. I’ve never had brass fail on me so quickly, but I can’t remember ever using Hornady brass for reloads. The problem now is that I had planned to use all the Hornady brass for reloads in the future. I’ll anneal and see if that gives me more case life.

I have some new Lapua cases but maybe I should acquire some more good brass if I can find it.

Good to know that my problem isn’t the barrel, so there’s that bit of good news.

Get some boxes of PPU and see how that does for reloading. It shoots pretty well as loaded ammo for me too. I don't reload yet but I'm saving all my brass.

To elimnate your problem if it is your gun, shoot another brand of brass, load the same load and go from there. If it splits brass
again, you may have a problem. Then get some one to measure the chamber area, barrel headspace.
On the brass, im getting about 6 to 7 loads per brass on some old Lake City stuff i landed years ago for use my Match grade
M1A, load the standard 41grn of 4895 mil spec loads. I know Lake City can take a beating more than commercial smaller
calibers.

Thats my rant for the aftrernoon, back to polishing 10mm stuff......



shoot safe....

Yep. I use Hornady in my kids 6.5Grendel and I have 5-6 loads on some of them. Semi-autos may be harder on brass but I don't think the neck is affected any different, maybe I'm wrong. Regardless, anneal and go back to whatever you were before.