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Case-head seperation...

O

oneshot onekill

Gunny Sergeant
Full Member
Minuteman
Jul 29, 2008
1,955
16
61
DeBary, Florida
#1
Hey Y'all,
I need a little help from the Vast SH Knowledge Base! Last week I reloaded some FGMM Brass and I seem to be blowing it all up as I go along! Here's the rundown:

I bought the FGMM 168's about 3 months ago. They were new. I fired them. I reloaded the brass once with 155 SMK's, CCI200 primers and 43gr of Benchmark powder and only neck-sized them. Empties were all at or slightly below 2.015" after sizing. No problems except they were a little tight closing the bolt. Bullets were seated to the standard 2.800" COAL so the tightness was because of the shoulders. I verified this by pulling a round out after closing the bolt on it several times and examining it (a little shiney on the edge of the shoulder) I decided to full-length size them this time and try 168's again because the 155's weren't all that accurate. I use a case-length gauge to check every empty shell for shoulder depth and then trim them to 2.015". This time I used 43gr of IMR4064 behind them. Went to the range on Friday and every round I fired split the brass and showed signs of over-pressure. I stopped after 5. Since I had full-length sized them and made the length 2.800" I decided to try them in another rifle I have that I know has a good chamber and they all split in it too! I tried the other rifle because I wanted to be sure it wasn't a head-space issue on the first rifle. So WTF?! Please ask questions if I missed anything. I'm trying to figure out why FGMM Brass that was only reloaded twice would separate like that... And why there were signs of over-pressure! I'm left scratching my head and pulling the bullets and powder from that brass. I even checked the charge on several of the ones I pulled and it was within a tenth of a grain (only because a little powder gets stuck in my bullet puller). Is 43gr. of IMR4064 pushing the limit? Here are pictures of one of the shells. What say ye oh wise ones?
w97j4k.jpg
i41qft.jpg
 
#2
Re: Case-head seperation...

The cases were sized too short for your chamber. The case stretched and the brass flowed, thinning at the area just ahead of the case head.

Properly setting your dies to match your rifles chamber will help a lot. That's just one reason I full length size every time. I don't have to keep up with little piles of brass neck sized 1X, 2X, 3X... etc.
 
#3
Re: Case-head seperation...

I have to agree with Victor. Anytime I have seen a case seperation like this it is usually traced back to setting the shoulders back to far. I have also never been fond of Federal brass past the first firing.
 
#4
Re: Case-head seperation...

This past week seems to have been full of FL sizing and oversizing issues on the hide.

Also, not sure about the new federal brass, but some of the older stuff from the start of the year and earlier, is the thinner fed stuff... I have heard of short case life on this type of brass, especially for guys running either hot loads, dies not set properly or not annealing, or a combination of.

Get yourself the hornady or sinclair comparitor and headspace tools. Measure up a bit of brass that struggles to chamber after firing. Set up your die so its bumping it back 0.001 at a time. Try to chamber. Stop when you go from not chambering easy to chambering like a charm. Lock the die and leave it.

If you feel slight resistence when chambering, thats the shoulder rubbing against the chamber wall. Back it off slightly.

The tools really help. The difference between me undersizing, and sizing more than 0.001 - 0.002 is a tiny fraction... probably 1/16th of a turn on my die. Thats why its best to use tools to verify
 
#5
Re: Case-head seperation...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">The cases were sized too short for your chamber. The case stretched and the brass flowed, thinning at the area just ahead of the case head.

Properly setting your dies to match your rifles chamber will help a lot. That's just one reason I full length size every time. I don't have to keep up with little piles of brass neck sized 1X, 2X, 3X... etc. </div></div>

I appreciate all of the responses so far but let me ask about this one... Do you mean the cases were too short from Federal? Or when I decided to full-length size them? When I full length sized them I used a case-length gauge to check every round to be sure I didn't bump the shoulders too much. The last time I set the shoulders back too far it pushed out the primers when I fired them so I'm pretty careful to check every round for case length (which includes shoulder position) Are these gauges not able to give you an accurate assessment? Because what you're saying makes sense...
 
#6
Re: Case-head seperation...

Here's something else. When I first fired these FGMM's I dropped the fired shells into my case-length gauge and they still fit. They were a little snug but they still went in and were still within the gauge's tolerance. I just had to pop them out with a cleaning rod. This makes me think my chamber is really good. I've done this same test with rounds I fired years ago in other rifles and the cases stop about halfway in and will go no further.
 
#7
Re: Case-head seperation...

ALL FACTORY AMMO is sized to fit the smallest SAAMI chamber.

What caused the case head to sperate is YOUR DIE is not set to YOUR CHAMBER. It usually takes more than one sizing to do it. But it is possible.

Using a guage is fine if your chamber is set to that guage. 95% are NOT. There are ways to set dies without guages like the Stoney Point / Hornady design type. But that type guage attached to a digital caliper and PRACTICE ON USING IT, is by far the best way to do it.

While Federal brass is softer than some others, I would wager a statement that your die being set wrong is the reason for the seperation.
 
#10
Re: Case-head seperation...

Right after my last post I duplicated the load using Lake City Brass I had previously full-length sized and took a quick trip out to the range to test the 5 I made up real quick. None of them split... And why did my Federal Brass show signs of over-pressure? The LC brass didn't.

I have the L.E. Wilson type gauge. So far it's been perfect in measuring all other brass. Not meaning to be an ass but MY DIE hasn't had problems sizing to MY CHAMBER with any other brass. At least as far as I know because I haven't had problems with any other brass. I use exactly the same method on all brass that I full-length size and this Federal brass is the only brass I apparently sized wrong? That doesn't make sense to me.

Bottom line... I'll avoid Federal Brass and full-length sizing at all cost. Neck-sized bullets are better anyway! Thanks for the help guys! I'll write it off to shitty brass!
 
#11
Re: Case-head seperation...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body">Right after my last post I duplicated the load using Lake City Brass I had previously full-length sized and took a quick trip out to the range to test the 5 I made up real quick. None of them split... And why did my Federal Brass show signs of over-pressure? The LC brass didn't.

I have the L.E. Wilson type gauge. So far it's been perfect in measuring all other brass. Not meaning to be an ass but MY DIE hasn't had problems sizing to MY CHAMBER with any other brass. At least as far as I know because I haven't had problems with any other brass. I use exactly the same method on all brass that I full-length size and this Federal brass is the only brass I apparently sized wrong? That doesn't make sense to me.

Bottom line... I'll avoid Federal Brass and full-length sizing at all cost. Neck-sized bullets are better anyway! Thanks for the help guys! I'll write it off to shitty brass! </div></div>

You probably should have just left that first batch alone--the snugly fitting ones.

You can't always 'neck' size, as that brass will eventually grow (head to shoulder) too long for you to chamber.

Wilson case gages give you a rudimentary snapshot of how long that shoulder is, as well as how long your entire case is, but both are imprecise.

You need a headspace gage, like the RCBS Precision Mic, the Hornady/Stoney Point gages, or the one that Sniclair makes.

Chris
 
#12
Re: Case-head seperation...

I don't know about the larger calibers, but general consensus seems to be, stay away from Federal brass in .223.
If you do reload it, use a mild charge and leave it lay. I have read, one more than one occasion, reports of loose primer pockets after the first firing.
This is why I won't buy anything Federal offers in metallic cartridges.
 
#14
Re: Case-head seperation...

In all honesty, I have loaded 308 FGMM brass after shooting the original factory load 4X with no problem. At 6X I started finding internal cracking using a dental probe to check inside. I'm bumping the shoulders back about .002" The Wilson guage can't tell anything that close. The best I have been able to do with the several Wilson's that I have is in the .008 to .010"

The load I was using at the time was Winchester Large Rifle primers, IMR 4895 and 168 SMKs in the ball park of 2750 to 2800 fps.

The Federal brass IS SOFTER than most other American commercial brass. But that softness allows the brass to seal off better on the FIRST firing. That's what it was meant to do.

If you want to get the most load cycles on accurate ammo, set your full length sizing die or body shoulder bump die to move your shoulder back .002" and load slightly less than maximum loads.

Good luck.
 
#15
Re: Case-head seperation...

All the information I got here is great and I appreciate it but one part of the question wasn't answered... Why would I have seen signs of over-pressure along with the separation? Is that a normal side effect?
 
#17
Re: Case-head seperation...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rrflyer</div><div class="ubbcode-body">What signs of over pressure did you get? </div></div>
Although you can't see it in my picture the primer is extremely flattened and is starting to flow into the firing pin hole. Also you can see in the picture that the ejector has left a substantial impression on the back of the brass.
 
#19
Re: Case-head seperation...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">The cases were sized too short for your chamber. The case stretched and the brass flowed, thinning at the area just ahead of the case head.

Properly setting your dies to match your rifles chamber will help a lot. That's just one reason I full length size every time. I don't have to keep up with little piles of brass neck sized 1X, 2X, 3X... etc. </div></div>

+1
 
#20
Re: Case-head seperation...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DavidD</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">The cases were sized too short for your chamber. The case stretched and the brass flowed, thinning at the area just ahead of the case head.

Properly setting your dies to match your rifles chamber will help a lot. That's just one reason I full length size every time. I don't have to keep up with little piles of brass neck sized 1X, 2X, 3X... etc. </div></div>

+1
</div></div>
Yea... I get that. The only reason I posted the original question is because I reload ALL of my rounds with the same equipment and to the same specs as far as case size and this Federal Brass is the only brass I've had a problem with. Apparently it's just crappy brass.
 
#21
Re: Case-head seperation...

Why don't you weigh a few of the fgm cases and a few of the lc. Sierra lists
43.3 as max load, which sounds low, but I know in the .223 the fm cases are the heaviest and with a smaller inside capacity your pressures go way up. I have seen
primer pockets loosen on federal cases but haven't seen head separation occur
any worse than others. The head marks, bent rim and somewhat flat primer look
like it was a warm load. Also seeing you are in Fl. did you shoot any of the three
firings in wet weather or with condensation in the chamber/ on the shells?
 
#22
Re: Case-head seperation...

I'm pretty sure the LC cases are thicker and therefore have less capacity. I would imagine those would be the ones that showed over-pressure signs but they didn't.

The weather has been pretty dry here lately being almost Winter and all. BRRR... Temps in the 70's during the day and lower 50's at night! Although this weekend was a little more humid and warm but not really "wet".
 
#23
Re: Case-head seperation...

Assumptions can get you hurt. LC is not heavier. LC match is about the same.
I don't have federal match cases that aren't loaded but the FC cases can run
as light as 158 to as heavy as 178, about the same as LC match. IIRC the FGM is
190 to 195. Seeing brass has about an 8.5:1 ratio with water that could put
your loads right at max in IMR's data and over max using Sierras.
 
#24
Re: Case-head seperation...

Federal bras is known to be shitty. That is nothing new. I kinda laugh when people snatch that shit up on the classified like it's gold.
 
#25
Re: Case-head seperation...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bigwheeler</div><div class="ubbcode-body"> Assumptions can get you hurt. LC is not heavier. LC match is about the same.
I don't have federal match cases that aren't loaded but the FC cases can run
as light as 158 to as heavy as 178, about the same as LC match. IIRC the FGM is
190 to 195. Seeing brass has about an 8.5:1 ratio with water that could put
your loads right at max in IMR's data and over max using Sierras. </div></div>

I didn't know there was a difference in LC but FWIW my brass is "Match" brass and most of it is from the 70's and pretty damn thick. I'd venture to guess it's thicker than the Federal stuff but I'll weigh some when I get home and let you know.
 
#27
Re: Case-head seperation...

Older is better again. But back to the problem, If you know you didn't resize
too small then they were way small from the factory. They stretched a lot at one
time or another to thin out that much and crack.
 
#28
Re: Case-head seperation...

The main reason I don't think I sized them too short is because I check each round with a case-length gauge which I understand to be relatively inaccurate. So as soon as I can I'll get the right gauges. For now, I've loaded up more of my LC brass for this rifle and I'll see how it goes.
 
#29
Re: Case-head seperation...

Case gauges are supposed to gauge within saami specs. I don't buy the inaccurate
claims. We managed to get along with no gauges until very recent history. I got
thinking back over the years and I had the same problem one time with a 22-250.
I had two different brands of shell holders, being such a popular base size, and
had used the wrong one for the die setup.
I would sure like to know how it happened for you as well. It's the only way to
avoid the same problem in the future. Bad brass is possible, but Federal has a
rep. for being softer not harder than other brands. With as many guys shooting
and loading 308 a brass problem would or will certainly become public fodder.
Keep us posted please. Wish I could have helped.
 
#30
Re: Case-head seperation...

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
No problems except they were a little tight closing the bolt.
</div></div>

I had a Palma 95 chambered Krieger a few years ago.

Federal GMM out of the box would not fire in it, yet every other brand of ammo, including BHA would. Could not close the bolt.

I dunno what it is about their brass but IMHO it just sucks.

Now I've had ONE case head separation on BHA but I FL resized each and every time, I also have a factory chamber in my rifle, bit larger than the norm.

and I've reloaded them 7 times.

So one out of 1200 is acceptable - what you have is not.
 
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