How common are split necks...

[LocoGringo]

...after 1 loading? I'm going through the Remington brass I used to make some test loads for my Bergara B14 7mm-08 and out of 50 rounds, I found 4 cases with split necks. I haven't had a split neck yet with any loads I've done ranging from .308 to previous 7mm-08 loads for a different rifle to 6.8 SPC.

This brass was saved from commercially loaded ammo and has only been fired once. It is not range pickup or bought from another source. I cleaned this brass by wet tumbling with water, stainless steel pins, Dawn dishwashing detergent and a little bit of lemishine for no more than 4 hours (probably a bit less). The max load for testing I used was Hornady 139 grain BTSP bullet, Remington brass, Federal 210M primer and 43 grains of Varget powder loaded to .05" off of the lands and grooves. I trimmed the brass to 2.030" which is right in the middle of what my Hornady manual recommends. My test loads ranged from 41.0-43.0 grains of Varget.

So my questions are these:
Am I unknowingly loading hot? Or...
Is Remington brass really this weak? Or...
Is there a potential flaw in my chamber? Or...

 

[Charlie98]

I've found newer brass to not be as durable as older brass. Yes, yes, I know... I sound like one of those prune-faced bitter old-timers... "Back in MY day...." ...but it's true. I'm actually a big fan of RP brass, but I'll acknowledge that every maker has had a bad lot or two. Easiest way to get more life out of your necks is to anneal them.

I have had brass crack on the first firing, too... very likely almost everyone has. I have had brass lots that soldier on forever (RP .41MAG brass,) and I have had lots go south on me pretty fast (Starline .38SPC brass.)

I trimmed the brass to 2.030" which is right in the middle of what my Hornady manual recommends.

Why 'in the middle?' Why not the 'trim to' length in the manual?

 

[Slamfire]

How old was the commercially loaded ammunition when you fired it?

You have been taught to discount the age of gunpowder, probably taught that gunpowder lasts forever, and if it fails, it fails benignly. Am I correct?

Well, none of the above is true. Gunpowder is breaking down the day it is leaving the factory. There are stabilizers in gunpowder, designed to soak up the NOx that results from nitrocellulose deterioration, but in time, the stabilizer runs out. Gunpowder lifetime is so unpredictable, mostly depending how much acid was left in the nitrocellulose and storage temperatures. NOx is a spectrum of chemicals, one of which is NO2, nitrogen dioxide. Which is a horrible oxidizer, and when NO2 runs into a water molecule, (call it humidity) it turns into nitric acid gas. When the stabilizer runs low, you have nitric acid gas and NO2 in the case. And that attacks brass.




I did not know any better about the lifetime of gunpowder when I reloaded these cases back early 1990's. Well guess what happened in 2017



sometimes the NOx leaks out of the case, pools in the cartridge box, and you see this.









a bud purchased LC 1969 pulldown IMR 4895. You get what you pay for







this might have been some of the pulldown IMR 4895 I purchased. I loaded ammo boxes of good LC match brass, and upon firing, case neck splits and case head cracks. The brass had been weakened by gunpowder outgassing NOx





More pulldown powder purchased at Camp Perry.




Vihtavuori powder from the 1990's has been going bad all over the place. Happened to me. The Finns live in a very cold place, maybe they skimp on stabilizer.




So, lets say what you are seeing is the result of deteriorating gunpowder attacking your brass. Then to state it briefly: you are up the creek. You can shoot the stuff until all case necks crack. You do run the risk of case head separations, maybe even a pin hole that finally works its way through the case head. And, there is nothing you can do to fix this. No amount of washing, hand waving, rain dancing is going to reverse corrosion. Train wreck already happened.

 

[N555]

Depends.
30-30 likes to split bodies 1/2 to 3/4 way down the case after several loadings.
My Mauser likes to split new brass at the shoulder but usually does not crack fire formed.
Older brass is better. Cheap brass seems to have gotten cheaper good brass is still good.
To get new brass as good as old brass you have to pay for it. Lupula, nozler, alpha, starline, etc.

 

[film495]

4 out of 50 doesn't seem too bad, sound like the brass isn't very good. I've never annealed brass, but maybe that would help if you want to put in the effort for that brass.

 

[JmacD]

I recently (within the last year) went through all my 250 savage brass. I had a bunch of split necks. All of them were on RP headstamp. Some once fired. Some was bought new in component form. All split on first firing/ reloading. I’m going to anneal the RP I have and see what happens. I’ve got a few hundred other brands. Maybe I will outlast this barrel… but I’ve got the quarter bore bug, and I’m an old soul… I’m about to build another in the same cartridge… anyway! I digress. My personal experience with RP has been problematic.

 

[Blue68f100]

I've had several mfg split on he first firing. Mfg are do the bare minimum to make brass. Every cycle they can cut out saves them money and increase production speed. Their only requirement is to hold and fire for 1 firing. This is one of the reason I started annealing every thing no matter the number of firing. Since I've started annealing I have not have a single piece of brass fail due to split necks or shoulder.

 

[LocoGringo]

Why 'in the middle?' Why not the 'trim to' length in the manual?

My thinking is to lose less brass from “growth” after firing? Is there an advantage to trimming to the minimum length? Asking sincerely.

 

[LocoGringo]

To @Slamfire, I’ve not been taught that ammo and powder lasts forever, but I’ve seen lots of old ammo that had no visible defects. Your chemistry lesson is hugely informative and I’m grateful. Now I feel like I need to load all of my ammo and shoot it ASAP.

I can’t say exactly how old this ammo is, but I’m sure it’s less than 10 years old. I bought it new to shoot through my son’s custom rifle and that rifle has been finished less than 10 years.

 

[Charlie98]

My thinking is to lose less brass from “growth” after firing? Is there an advantage to trimming to the minimum length? Asking sincerely.

well… if you are crimping, it probably doesn’t matter. If you don’t…. And trim to minimum, yiu will likely reduce the number of times you will have to trim… unless you trim regardless, which some do.

 

[LocoGringo]

well… if you are crimping, it probably doesn’t matter. If you don’t…. And trim to minimum, yiu will likely reduce the number of times you will have to trim… unless you trim regardless, which some do.

I'm not crimping.

So you're saying that the brass is gonna grow no matter what, so trim less often by trimming to minimum, correct?

 

[Charlie98]

I'm not crimping.

So you're saying that the brass is gonna grow no matter what, so trim less often by trimming to minimum, correct?

that’s my thought…

 

[cfullgraf]

I have a 6.5x54 Kurz Mauser that I have to form cases for. 308 Win and 7mm-08 work well but they are a bit short to start with. 7x57 cases seem to work the best.

In all situations, the cases fail mostly due to neck splits. Annealing may help.

Interesting, I reformed some nickel plated Fed 308 Win cases and they failed due to neck splits on the first firing.

Virtually all my other bottle neck rifle case cartridges fail for other reasons than neck splits. Most are commercially available cartridges but some are former wildcats like 22x6.8.

I recently built a 22 Bench Rest rifle for Prairie dog work. Cases are formed from 6mm Bench Rest. I don’t know how durable the cases are yet.

 

[Nature Boy]

I loose the primer pockets before I split necks

 

[Slamfire]

To @Slamfire, I’ve not been taught that ammo and powder lasts forever, but I’ve seen lots of old ammo that had no visible defects. Your chemistry lesson is hugely informative and I’m grateful. Now I feel like I need to load all of my ammo and shoot it ASAP.

I can’t say exactly how old this ammo is, but I’m sure it’s less than 10 years old. I bought it new to shoot through my son’s custom rifle and that rifle has been finished less than 10 years.

The thing is, gunpowder lifetime is highly unpredictable. Maybe your ammunition was loaded with powder from the same manufacturer as this ammunition:







Maybe Remington loaded your cases with IMR 4007. I recall IMR 4007 first came out in 2007, so a 2015 powder recall of all lots would involve powder that was no more than eight years old down to new powder. That's not particularly reassuring.





no one I know noticed the "rapid deterioration", or understood the implications.




maybe your cases were loaded with some of this powder. I will bet 4350 is a great powder in the 7mm case. Do the math, now how old can this powder be?








Heat goes a long way in reducing gunpowder lifetime.



I consider it unusual to have four case neck splits out of fifty once fired cases . Maybe it is a statistical fluke. If it keeps up, it ain't.

 

[LocoGringo]

I consider it unusual to have four case neck splits out of fifty once fired cases . Maybe it is a statistical fluke. If it keeps up, it ain't.

This is what I thought also, especially considering that I've never seen a split case neck come out of a gun I've shot.

I don't have an annealer, yet. I will test some more and see if more case necks split. If they do, I think I'll ditch Remington brass. I've never been a fan of Remington ammo anyway.

 

[Slamfire]

Depends.
30-30 likes to split bodies 1/2 to 3/4 way down the case after several loadings.

I suspect that you have never measured the base to shoulder of a fired case, and compared against a new case. My Marlin chamber had to have been reamed with a bratwurst. Look at how much the shoulder has to move forward before it touches the chamber shoulder. Since the 30-30 is a rimmed case, it head spaces on the rim. Base to shoulder distance is not controlled. Marlin New Haven was not selling their rifles to target shooters or reloaders. They made rifles for those who never cleaned their guns, and shot grand dad's rusty old ammunition at deer 50 yards away. I measured the height of the rim above the case gauge for eight fired cases. One shoulder moved 0.031 inches. That's three one hundredths of an inch!. A secondary use for Marlin chambers is to rent them out for Zeppelin parking.



With that much clearance between case shoulder and chamber shoulder, you can expect the case to separate in a couple of firings.

To extend your case life, fire them lubed.




A lubricated case will not adhere to the chamber walls. What happens during ignition, the case slides back to the bolt face, the shoulders fold out, and you end up with a stress free, perfectly fireformed case. Then, bump the should back about 0.003" inches and no more.

My Mauser likes to split new brass at the shoulder but usually does not crack fire formed.

A guess is that your Mauser was also chamber reamed with a bratwurst. One that was big in the shoulder so that any crappy wartime ammunition would chamber. Reloading was not a consider for service ammunition. Issue ammunition was expected to go bang once, be extracted, and left on the ground. Battles were not halted for brass collection. If brass has to stretch too much, it will rupture.

 

[jmorris]

I loose the primer pockets before I split necks

What are the conditions that allow for that?

 

[Slamfire]

This is what I thought also, especially considering that I've never seen a split case neck come out of a gun I've shot.

I don't have an annealer, yet. I will test some more and see if more case necks split. If they do, I think I'll ditch Remington brass. I've never been a fan of Remington ammo anyway.

I wish I could say Remington brass is perfect, made by monks who dedicate their lives to the perfection of ammunition, and never tainted by poor subcontractor management and faulty in house inspection. But, I can't. It is possible that the brass, and then the case manufacturing process was messed up for your lot. If you had access to someone with an electron microscope, they might see corrosion cracking that is invisible to the eye ball.

 

[Slamfire]

What are the conditions that allow for that?

Typically about half the primer pocket cup is outside the chamber, if not more. Given thrust against the bolt face, that cup spreads outwards. I experienced that with 308 LC brass I fired 22 times in a M1a. I also found that I had to ream the pocket to depth, as the center of the pocket, where the primer hole is, also collapses down.

Make a cup out of play dough. Put the rim down, press on the back. See what happens.

 

[jmorris]

I was talking about the rest of the case being fine long enough for the primer pocket to finally get loose vs the neck splitting early.

There are conditions, where this can always be the case (no pun intended).

 

[N555]

I suspect that you have never measured the base to shoulder of a fired case, and compared against a new case. My Marlin chamber had to have been reamed with a bratwurst. Look at how much the shoulder has to move forward before it touches the chamber shoulder. Since the 30-30 is a rimmed case, it head spaces on the rim. Base to shoulder distance is not controlled. Marlin New Haven was not selling their rifles to target shooters or reloaders. They made rifles for those who never cleaned their guns, and shot grand dad's rusty old ammunition at deer 50 yards away. I measured the height of the rim above the case gauge for eight fired cases. One shoulder moved 0.031 inches. That's three one hundredths of an inch!. A secondary use for Marlin chambers is to rent them out for Zeppelin parking.

View attachment 1145554

With that much clearance between case shoulder and chamber shoulder, you can expect the case to separate in a couple of firings.

To extend your case life, fire them lubed.


View attachment 1145555

A lubricated case will not adhere to the chamber walls. What happens during ignition, the case slides back to the bolt face, the shoulders fold out, and you end up with a stress free, perfectly fireformed case. Then, bump the should back about 0.003" inches and no more.



A guess is that your Mauser was also chamber reamed with a bratwurst. One that was big in the shoulder so that any crappy wartime ammunition would chamber. Reloading was not a consider for service ammunition. Issue ammunition was expected to go bang once, be extracted, and left on the ground. Battles were not halted for brass collection. If brass has to stretch too much, it will rupture.

Now I gap my 30-30 die and shell holder about 13 to 14 thousands. 30-30 chamber specs are more like suggestions. Been gapping the die to shell holder for years now.
I was getting body splits after around 6 to 8 firings when putting the shell all the way into the die.

It does look like the mauser was reamed with a brat.
Not much I can do about it when running new brass. I get the most splits with British 43 head stamps.

 

[Nature Boy]

What are the conditions that allow for that?

Generally these are loads in .308 and .223 that are running at their limit for F Class matches.

For example, using standard .308 Win Lapua brass with these loads would only allow 3-4 reloads before I would have to scrap them for loose pockets. Switching to .308 Palma brass with small primer pockets yielded +2X in case life. I suppose having more brass surrounding the pocket allows them to better handle the forces exerted on the case head.

Now, if I’m loading more pedestrian reloads, like I do for hunting rounds, I can expect to see signs of case head separation before split necks.

So in my case, split necks are very unlikely and uncommon.

 

[BBarn]

I have a batch of 243 brass that was prone to splitting necks from the start. Loads were well below maximum. Annealing the necks seemed to significantly reduce the propensity of that brass lot to split at the neck. It seems some batches/brands are harder and/or more brittle than others.

 

[AJC1]

Now I gap my 30-30 die and shell holder about 13 to 14 thousands. 30-30 chamber specs are more like suggestions. Been gapping the die to shell holder for years now.
I was getting body splits after around 6 to 8 firings when putting the shell all the way into the die.

It does look like the mauser was reamed with a brat.
Not much I can do about it when running new brass. I get the most splits with British 43 head stamps.

30-30 has such a long history and the type of gun it was used in, makes me believe there are chambers from mild to wild as far as specifications go. If ever a caliber were to be treated as an individual that gets my vote. I'm shooting an 80s 94 and I'm trying to figure out just how cavernous my chamber is.