Analyze this brass

[GRIM]

Ok - this brass was shot in my 300 Rem Ultra Mag. 190 grain SMK bullet, 84.0 grains of 4831SC, Winchester 9 1/2 Mag primer and new Remington brass. Rifle is a Nesika Bay action with a 30" Hart barrel.

I remember a while back that Sierra loading data re-did their 300 RUM data and were WAY over the max charge for my setup. So I pulled a ton of bullets and started over. My new load is definately under the revised max powder charge of 85.3 for a SMK 190 bullet.


So what is the story with the shoulder caving like this?! Is gas getting by the neck and crushing it in from outside or is the brass bad and collapsing under suckage of pressure (new word - suckage), or ???

 

[Dogtown]

Re: Analyze this brass

I had a similar problem a couple years ago with my initial .408 loads. EDM brass was too soft and couldn't handle the hotter loads...

 

[GRIM]

Re: Analyze this brass

Was the EDM brass made by Remington or was it EDM's own creation?

 

[Dogtown]

Re: Analyze this brass

I don't know for certain - but I was told they were part of a custom order from Bertram that was stamped EDM. Regardless, TTI and Jamison brass did just fine with an identical load and came case dimensions.

 

[GRIM]

Re: Analyze this brass

Thanks for the good info. I've been really frustrated about this. My first batch of stuff that I worked up was fine so it looks like I've got some bad brass...

 

[nicholst55]

Re: Analyze this brass

I have seen similar results with too light of a load; there simply wasn't enough pressure to completely seal the chamber, and gas leaking back collapsed the shoulder area.

In my case, bumping the load up a bit cured the problem.

 

[zenbiker]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nicholst55</div><div class="ubbcode-body">I have seen similar results with too light of a load; there simply wasn't enough pressure to completely seal the chamber, and gas leaking back collapsed the shoulder area.

In my case, bumping the load up a bit cured the problem. </div></div>

nichols hit the nail on the head. Those creases are caused by failure of the neck to seal, allowing gases back into the chamber. This can be caused by very light loads and by too long a jump between the case mouth and the leade of the barrel; if the leade is too long either due to erosion or the bullet too short for the designed leade, the bullet will "float" in the freebore space unsupported by the case mouth or the barrel leade, again allowing gas back into the chamber.

 

[zenbiker]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dogtown</div><div class="ubbcode-body">I had a similar problem a couple years ago with my initial .408 loads. EDM brass was too soft and couldn't handle the hotter loads...

</div></div>

Dog, these cases also show a headspace problem. Those case head separations are caused by cases that are sized too far back from the chamber headspace. Do you set your sizing die to your fired cases?

 

[GRIM]

Re: Analyze this brass

Well my original load was 89.4 grains of 4831SC with a SMK190 and it shot 1/4 minute and the brass was fine, shoulders weren't collapsed. Shot nearly 400 rounds with it and no ill effects.

Got it re-barreled and it starts doing this. Since the load hadn't changed it leaves me to believe that I'd better measure the bullet jump again.

Thanks guys.

 

[Clark]

Re: Analyze this brass

On planet earth, suckage can only amount to 14.7 psi.

The area that is caved in is a small fraction of a square inch.

Even if the brass is soft, it will not cave in with 14.7 pounds of force with your finger tip.

What does it all mean?
That brass was not a victim of suckage, but pushing from the outside.

What was pushing it could be a grain of powder, a collision on ejection, getting stepped on, the oil in the chamber Dieseling, warping from being stretched by the chamber, etc. But whatever it was, it came from the outside.

 

[spaniel]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GRIM</div><div class="ubbcode-body">

Got it re-barreled </div></div>

Bingo!

 

[Dogtown]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1ZNUF</div><div class="ubbcode-body">Dog, these cases also show a headspace problem. Those case head separations are caused by cases that are sized too far back from the chamber headspace. Do you set your sizing die to your fired cases?</div></div>

Believe me, I thought the same thing for a while there. I ran through all kinds of different scenarios, but the bottom line was this particular batch of brass had problems when the other brass didn't. When nothing was working right I used factory Cheytac & TTI ammo as a base spec to start over from. I re-did everything, uniform trim length, neck sizing and tension, powder charges from 124gr to 129gr, etc. The only thing that made sense to me was that the brass was too soft.

Yes, it was weird.

 

[GRIM]

Re: Analyze this brass

Funny thing is that it didn't do this on the new barrel during break-in. I suspect that it's the Rem brass as I somewhere along the way I got a new batch of Rem brass worked into my loads and this started happening.

Who else makes 300 RUM brass?

It's NOT suckage? Man..... wait until I explain this to my wife - it will change our WHOLE relationship.

 

[former naval person]

Re: Analyze this brass

1ZNUF is on target I believe. My humble diagnosis is 1...excess headspace on the new barrel coupled with 2...low pressure loads. The reason the older brass didn't do that on breakin is probably twofold also...work hardening of the brass and previous expansion of the base in the old chamber that prevented the firing pin from driving the case too deep in the new chamber. JMHO

 

[Innovative]

Re: Analyze this brass

Grim .....

You're handloads have too much clearance (at the shoulder) in your chamber. I always prefer to use a FL die. However, it's important to "measure" this clearance, and set your die height accurately. Check out this link Article on Headspace Separation

- Innovative

 

[was21]

Re: Analyze this brass

Excess headspace for sure.

 

[Downzero]

Re: Analyze this brass

Why do people not know that they have to use a chamber gauge to set up the sizing die?

 

[mdesign]

Re: Analyze this brass

Only time I have ever seen this was with brass that had been resized too much and was not sealing up the chamber allowing pressure to come back.

I would definitely check how much you are resizing. Only go about .001 less than a case fired in your chamber.

 

[GRIM]

Re: Analyze this brass

Do all headspace issues have to show the ring around the case body or can you just have the caved in shoulder without the separation ring?

It's funny how I got about 700 rds down the first barrel and 100 rds down the second barrel without any of these signs before this started happening. I did get another new lot of Rem brass somewhere after it got re-barreled.

All of the reloads have been new brass so far but I'm going to tumble and reload some of the once fired brass to see what happens. I'll check the full-sizing as well. Thanks for the pics and btdt Dogtown.

 

[bfoosh006]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dogtown</div><div class="ubbcode-body">I had a similar problem a couple years ago with my initial .408 loads. EDM brass was too soft and couldn't handle the hotter loads...

</div></div>

No offense, but...Amazing example of "Case Head Separation"

 

[Dogtown]

Re: Analyze this brass

Indeed. Like I said, it was baffling because this was virgin brass and other brass brands used to the exact same spec faired fine. I wasted a lot of time and money trying to diagnose this one.

Check out the primers and again, this was a very middle of the road load...

GRIM, sorry to sort of hijack your thread...

 

[former naval person]

Re: Analyze this brass

DOGTOWN...that is the perfect example of a little bit too much headspace cartridge...the firing pin drives the brass case and primer forward. The firing of the load at first extrudes the primer rearward, then the case head follows and reseats the primer...leaving the primer head perfectly flat against the bolt head. No matter if a bit low or a bit high in pressure. Headspace is the problem. JMHO

 

[GRIM]

Re: Analyze this brass

Hey - it's NEVER a hijack when we get good info going 'round. Thanks!

 

[Dogtown]

Re: Analyze this brass

Gotcha Naval...but then why does the other brass not have the same problem? Also, this isn't sized brass - it's virgin, so that would mean it was out of spec to begin with. Believe me, I initially came to the same conclusions, but was puzzled by the results testing with different brass.

 

[GRIM]

Re: Analyze this brass

Ok - a quick detour to primers for magnum loads... Anyone have answers?

1. Which magnum primer is hotter - meaning more flame on ignition?
Federal Mag or Rem 9 1/2 Mag?

2. Which primer metal material is softer after ignition? Or would flow more easily under pressure/heat?

Or are they all the same?

 

[bigwheeler]

Re: Analyze this brass

primers are all the same material .027 thick on the cups for large rifle. Federal 215's
are hotter than rem 9 1/2 mags as are CCI 250's and WLRM.

 

[zenbiker]

Re: Analyze this brass

Grim, you might want to get a headspace gauge as well. At the very least, you may need to reset your sizing die out farther.
Showing up after a rebarrel is a classic headspace issue.

 

[AJ300MAG]

Re: Analyze this brass

Isn't that ejector marks I see on two of the three pieces of brass (lower left, upper)?

 

[zenbiker]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AJ300MAG</div><div class="ubbcode-body">Isn't that ejector marks I see on two of the three pieces of brass (lower left, upper)? </div></div>

Just thinking the same thing myself. I hate to say such things, but I'm wondering if the reamer went just a tad too deep in this chamber...I think I can make out burnishing on the "1" on the lower right piece of brass. I think a headspace guage is in order here just to be sure.

 

[former naval person]

Re: Analyze this brass

My point exactly...new brass is usually at minimum already, which allows the case to move forward under the blow of the firing pin; then, with the case gripping the wall of the chamber, the primer backs out, then reseats when the case web/base junction stretches...separating the case at the web and flattening out the edges of the primers level with the case head. I'll bet that if you punch out a primer it will have an edge on it like a rivet where it expanded to fit the bevel on the primer pocket. The ejector mark is from the case backing off violently enough to mark the case head. You need to get the headspace checked. Make sure that the same manufacturer makes the guage as made the reamer. The used cases were somewhere between minimum new specs and fired expansion...they filled the chamber more fully and didn't get driven forward as much as virgin. JMHO

 

[Clark]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GRIM</div><div class="ubbcode-body">F...

It's NOT suckage? Man..... wait until I explain this to my wife - it will change our WHOLE relationship. </div></div>

Joke:
Q: What is the difference between a wife and a job?
A: After two years, a job starts to suck.

Merry Christmas!
I know what you didn't get this year: suckage.

 

[zenbiker]

Re: Analyze this brass

Just FYI (and this is sure to start a shitload of controversy), when I chamber, I run the finisher in until the bolt handle (with firing pin and plunger ejectors removed) will close smoothly on a "GO" gauge, but wil not even begin to close on the same gauge with a piece of Scotch Tape (.0015 to .002" thick) across the head of the GO gauge. An old gunsmithing trick taught to me by an old gunsmith, and considering my age, seems appropriate to use it. The point is, if you brass isn't within .001 to .002" of the headspace point (an annulus approximatley midway down the shoulder between the base of the neck and the body/shoulder junction), it will stretch and separate just in front of where the case begins to thin out in front of the base, just as we see here and described by Former Naval Person. If the gunsmith or CNC lathe ran the chamber too deep, any type of brass will fail. When the chamber is set right and the sizing die is set to match the chamber, the limit on brass life is ususally the primer pocket, not the body of the brass.in

Merry Christmas

 

[GRIM]

Re: Analyze this brass

Here's a follow up to the problem that I've been having with my 300 RUM rifle brass.

I dug out my once fired brass that shot just fine the first time and made crazy tiny groups (1/4 minute) and reloaded it a second time with 84.0 & 85.0 grains of 4831SC. The second fired brass came out just fine. I have been told that some of the Remington brass was the problem and I'm now starting to believe it. The two cases on the left were 84.0 grains and the three on the right were 85.0 grains and neither showed pressure signs. So now I'll be reloading my once fired brass until I can order some of the Federal brass - heard that it doesn't have the problem that I was encountering with some of the Remington brass.

 

[Country]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AJ300MAG</div><div class="ubbcode-body">Isn't that ejector marks I see on two of the three pieces of brass (lower left, upper)? </div></div>
I was going to say the same thing. To get an ejector hole mark like that there has to be high pressure involved I would think. I would be checking your powder type and charge weight in addition to headspace of cases.
Something is not right .
Always remember that the shot directly before a gun blowing up in someones face , never seems to raise any alarms and stop them shooting. They still continue on to that final destructive shot.
The reason is simple they are unable to recognise the warning signs , so every shot leading up is considered normal even if the cases are coming out in pieces . Take some time to reasses your load .

 

[Country]

Re: Analyze this brass

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GRIM</div><div class="ubbcode-body">Here's a follow up to the problem that I've been having with my 300 RUM rifle brass.

I dug out my once fired brass that shot just fine the first time and made crazy tiny groups (1/4 minute) and reloaded it a second time with 84.0 & 85.0 grains of 4831SC. The second fired brass came out just fine. I have been told that some of the Remington brass was the problem and I'm now starting to believe it. The two cases on the left were 84.0 grains and the three on the right were 85.0 grains and neither showed pressure signs. So now I'll be reloading my once fired brass until I can order some of the Federal brass - heard that it doesn't have the problem that I was encountering with some of the Remington brass.

</div></div>

You got me , I can't see what you are refering too in the pics? I must be missing something but they all look about the same to my poor old eyes.
Can you be a bit more specific?

 

[GRIM]

Re: Analyze this brass

I was just posting a follow up pic of the brass that I had just recently fired in the 300 RUM rifle. This brass didn't react the same way as the brass that is a the very top of this thread. No caved shoulder and it was loaded the very same way as the stuff that had a caved in shoulder. So I'm of the opinion that the second batch of 300 RUM brass that I started reloading was the culprit of being too hard in the neck and not expanding and sealing the gas when fired.
This latest brass pic that you cannot see any problems with is supposed to look like normal brass instead of having the shoulder caved in like the first pic posted.
First pic posted is new brass but from my second lot of brass
Last pic posted is of my once fired brass that is now twice fired and still looking good.

I did just get back from the Shot Show and I told the Remington brass rep about the shoulder caving in like it did and he said that I should try annealing the problematic brass to soften it up and try loading it again.