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Case Separation on Peterson 6.5 CM???

RaptorAddict

Sergeant of the Hide
Full Member
Minuteman
Oct 24, 2020
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Simi Valley, California
Was wondering if anyone can shed some light on how this happened.
F7C7A047-7133-4D2D-B9F3-0B392924FDC3.jpeg
I noticed a few other casings has a faint line starting in the same area. Was going into the 12th reload.
 
12th reload? The brass has run its course.

That said, pushing the shoulder back too far during sizing can cause premature head separation. I’d say 12 reloads is a good life.
 
Was wondering if anyone can shed some light on how this happened.View attachment 8311398 I noticed a few other casings has a faint line starting in the same area. Was going into the 12th reload.
I agree with the other's, it's most often the result of excess bumping of the case's shoulders. The more you minimize the amount of bump the longer the brass can last.

Also, part of the equation has to do with the brass's material itself and how hot the loads are. Some brass is a little more resistant to being stretched than others.

12 firings is not bad, but I'd expect a little more out of Peterson brass.
 
The other way to look at it is this: each firing costs:

$.10 primer
$.40 140 grain ELD-M
$.30 for 42 grains H4350

If the case costs $1.15 each and lasts 10 firings, that’s $0.12 per firing for the case.

They’re consumables. Retire them.

And ask: why am I not using Lapua brass?

If you want 20 firings per case, that’s where to look: industry standard.
 
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Do you know how much you’re bumping the shoulder?
It was always set at .002, which was always a hair shy of making the bolt lock in smooth without any binding while chambering. Hope I'm making sense. I'm 1 year green into this. I take all necessary steps in reloading, including annealing, so I tried to get as many reloads as possible. Charges aren't at maximum load.
 
The other way to look at it is this: each firing costs:

$.10 primer
$.40 140 grain ELD-M
$.30 for 42 grains H4350

If the case costs $1.15 each and lasts 10 firings, that’s $0.12 per firing for the case.

They’re consumables. Retire them.

And ask: why am I not using Lapua brass?

If you want 20 firings per case, that’s where to look: industry standard.
Heard Peterson was on par with Lapua. But I may just go Lapua this round and give those a shot. But I assume I'll have to develop another load using different brass?
 
If the case capacity is the same, you can use the same charge, and the former is easily measured.

Peterson has many fans including me, but Lapua remains the industry standard and its only peer is RWS or RUAG. Some will say ADG,
Some will say alpha, but like Peterson, whether or not the newcomers can hang is something that will require a generation of experience to determine for sure

Many of us, me included, will choose a caliber to shoot based on whether or not Lapua makes brass for that caliber. Thus I would choose 300 Norma over 300 Remington ultra magnum, even though the former is ballistically inferior.
 
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It was always set at .002, which was always a hair shy of making the bolt lock in smooth without any binding while chambering. Hope I'm making sense. I'm 1 year green into this. I take all necessary steps in reloading, including annealing, so I tried to get as many reloads as possible. Charges aren't at maximum load.
How often have you been measuring for your .002 of bump?

I ask because, I'd say it takes at least 2 firings to get the Peterson brass fire formed and your sizing die shouldn't be set for a bump until afterwards (like testing the cases after the first firing to see if they'll still chamber). If one sets their die for bump earlier than that and isn't checking afterwards, it could be the shoulder is being bumped more that one thought. This is just another thought running through my head that could lead to shorten case life.
 
How often have you been measuring for your .002 of bump?

I ask because, I'd say it takes at least 2 firings to get the Peterson brass fire formed and your sizing die shouldn't be set for a bump until afterwards (like testing the cases after the first firing to see if they'll still chamber). If one sets their die for bump earlier than that and isn't checking afterwards, it could be the shoulder is being bumped more that one thought. This is just another thought running through my head that could lead to shorten case life.
I started bumping I’d say at the 5th, or 6th reload. I started to look into it as I started to notice my reloads chambering with friction while locking down the bolt.
 
If you have only bumped the shoulder 6 times. You either had a lot of growth on the first six firings or you are bumping more than .002.
 
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Something else... how much does your die squeeze the shoulder diameter?

As an example, my 308 cases come out of the chamber around 0.455°, and they come out of most of my dies (Micron, Redding, Forster, Whidden) @ 0.453".

But... the same cases come out of my Redding small base die with the shoulder squeezed down to 0.450". Same shoulder 'bump', though.

The cases ran through that die definitely grew in length faster than the others... that brass has to come from somewhere... I'm guessing it didn't do the overall case life any favors.
 
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If you have only bumped the shoulder 6 times. You either had a lot of growth on the first six firings or you are bumping more than .002.

Something else... how much is your die squeeze the shoulder diameter?

As an example, my 308 cases come out of the chamber around 0.455°, and they come out of most of my dies (Micron, Redding, Forster, Whidden) @ 0.453".

But... the same cases come out of my Redding small base die with the shoulder squeezed down to 0.450". Same shoulder 'bump', though.

The cases ran through that die definitely grew in length faster than the others... that brass has to come from somewhere... I'm guessing it didn't do the overall case life any favors.
To be honest, I never thought about measuring the shoulder diameter. Special tool?
 
Something else... how much is your die squeeze the shoulder diameter?

I've had excessive case shoulder junction (CSJ) sizing also cause cause similar failures. I think my die was doing .005+ sizing, IIRC, which is excessive.
 
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You didn't say anything about what type of rifle, who built the barrel and whether or not you've checked the headspace on the rifle. If it was a new rifle or one that has been rebarreled its possible the headspace has opened up a little as the threads seat in the receiver. Also possible for the bolt lugs to seat a little which opens the headspace. There are many possibilities so you need to look a little more at some other things too.
Are you annealing the cases? How often, how far down does the heat go, are the cases stretching when you fire? 12 firings is pretty good for high power rifle cases.....
I've had great results with Petersen brass but only in a couple cals that I shoot it in.

Frank
 
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I've had excessive case shoulder junction (CSJ) sizing also cause cause similar failures. I think my die was doing .005+ sizing, IIRC, which is excessive.
Guilty here too. I had a chamber that would close on a field plus .003 and I was bumping .006 or .008 when I measured. They only lasted 5 or 6x. WA WA glad it was Hornady brass🤣🤣🤣
 
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Don’t just bin the brass. Throw it in a 5 gal bucket in the back of the garage. The last time I took brass to recycle, it was roughly $60 per bucket…
 
Just look for a local metal recycling place. They have a special category usually for a brass cartridge cases just like they offer different prices for different kinds of aluminum, such as cans versus siding, etc..
 
You didn't say anything about what type of rifle, who built the barrel and whether or not you've checked the headspace on the rifle. If it was a new rifle or one that has been rebarreled its possible the headspace has opened up a little as the threads seat in the receiver. Also possible for the bolt lugs to seat a little which opens the headspace. There are many possibilities so you need to look a little more at some other things too.
Are you annealing the cases? How often, how far down does the heat go, are the cases stretching when you fire? 12 firings is pretty good for high power rifle cases.....
I've had great results with Petersen brass but only in a couple cals that I shoot it in.

Frank
I shoot a Sako TRG 22. No mods. Yes I anneal at the start of every reload. I aim the flame just slightly above the shoulder, toward the bottom of the neck. The heat indication shows about 2-3 mm below the shoulder.
 
The other way to look at it is this: each firing costs:

$.10 primer
$.40 140 grain ELD-M
$.30 for 42 grains H4350

If the case costs $1.15 each and lasts 10 firings, that’s $0.12 per firing for the case.

They’re consumables. Retire them.

And ask: why am I not using Lapua brass?

If you want 20 firings per case, that’s where to look: industry standard.
The reason you use Lapua is its a superior brass alloy, and is thicker than just about everyone else.

It is harder, therefore the case heads will last much longer, and they are thicker resulting in less case stretch and less of a chance of case head separation. You also have more consistent neck thickness which results is lower SD/ES. Lastly, its actully cheaper than all the other premium brass. All the cheap shit like hornady, nosler, winchester, sig, ect is too soft and too thin.

You should be annealing to keep the case mouths softer , help with bullet release, sizing consistency and resisting splits.

If lapua is an option, its the answer and I own brass from Alpha, ADG, Peterson, Norma, ect. Hands down the best brass you can buy.

I assume 10 shots for any brass, as I will most likely loose them or trash them against some object by then. $100/100 comes out to about .10 per firing factored into reloading cost.

EDIT: Just read your subsequent post so not necessarily directed at you but anyone.