This is how IMMINENT CASEHEAD SEPARATION looks!

[turbo54]

I know a lot of y'all already know this, but thought I'd post a few pics. Maybe a sticky? Maybe add to Tresmon's reloading stickys?

This is a piece of Lapua 308 brass I've loaded about 8 or 9 times. Hot!! loads of 45.5gr Varget and a 175smk. I FLS every loading, but have my dies set to bump the shoulder .001". I use the Hornady insert type gage that attaches to my caliper.

In the first pic, you can see the "ring" around the body of the case, forward of the casehead. I scotch-brited one half of the sectioned case to make the ring really pop for the picture, but it is also clearly visible without Scotchbrite. This cartridge looked good going into the chamber, but had the ring after firing. It was very obvious then, because the brass wasn't tarnished at all.

Another view:

A look inside... you can see where the brass has thinned out and stretched. When new, the casewall thickness has a constant taper, from casehead to neck, and does NOT have the dip you see here.

Good shooting, and pay attention ALWAYS!

 

[seanhagerty]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Its a good idea to run a dental pick or a bent paperclip into every case after resizing. You can feel that "Dip" you show in your bottom picture.

Better safe than sorry.

 

[KYpatriot]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

thanks for taking the trouble to post these turbo...good work.

 

[High Binder]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Dang! Good catch and pics!

 

[Bigwheels]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Does this look the same for a belted magnum? I have some winchester brass for my 300wm that has 5-8 loads on them, & haven't felt any lip inside.

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bigwheels</div><div class="ubbcode-body">Does this look the same for a belted magnum? I have some winchester brass for my 300wm that has 5-8 loads on them, & haven't felt any lip inside. </div></div>

Yes. The ring of death will show up forward of the belt, and the "dip" inside will form the same - and be able to be felt with the pick/paperclip mentioned above.

 

[TexIndian]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bigwheels</div><div class="ubbcode-body">Does this look the same for a belted magnum? I have some winchester brass for my 300wm that has 5-8 loads on them, & haven't felt any lip inside. </div></div>

What Turbo said. You can go to This Thread to see some pics of belted magnums with the rings showing (Look down in the thread for pictures posted by ChrisGarrett).

 

[Bigwheels]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Thanks for the link. Luckily, I have never seen anything like that on my brass. I was expecting it to be much closer to the belt too. I'll check closer in the future.

 

[vonbalkenbush]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Very nice, I've got a bunch of Lapua .308 brass that is on it's 9th firing. I'll be keeping an eye out. Thank you Turbo.

 

[Innovative]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

The picture above clearly shows that case head separation begins on the inside of a case.

Case head separations are caused by pushing the shoulder back too far. When this happens, the shoulder gets blasted forward as it fills out the chamber. This excessive stretching of the case at every firing (cumulative damage) makes the brass paper thin, and it soon rips the case apart.

To make it easier to FL resize "accurately" I patented the tool that I use, the Digital Headspace Gauge.

 

[akmike]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Turbo, thanks much for this. Being new to loading this really helped me to know what to look for going foward.

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Innovative</div><div class="ubbcode-body">The picture above clearly shows that case head separation begins on the inside of a case.

Case head separations are caused by pushing the shoulder back too far. When this happens, the shoulder gets blasted forward as it fills out the chamber. This excessive stretching of the case at every firing (cumulative damage) makes the brass paper thin, and it soon rips the case apart.

To make it easier to FL resize "accurately" I patented the tool that I use, the Digital Headspace Gauge.



</div></div>

I slightly disagree.

I believe the firing pin impact drives the case forward in the chamber, such that the shoulder is firmly in contact with the chamber. Excessive headspace in thus situation would create a gap between casehead and boltface. Upon ignition and subsequent pressure rise, the portion of the case with no radial suppirt, and no chamber to "bite" into, blows rearward, in exactly the same spot every time, which is why the ring of death is so straight, and not wavy-gravy.

This excessive HS and blowback into the bolt face can/will also flatten primers and cause "ejector marks" to form, even though pressures may not be over the top.

 

[seanhagerty]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

I have never checked for the ring on unsized brass. I will start checking before resizing, to see if I can find it.

 

[jlow]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Innovative</div><div class="ubbcode-body">The picture above clearly shows that case head separation begins on the inside of a case.

Case head separations are caused by pushing the shoulder back too far. When this happens, the shoulder gets blasted forward as it fills out the chamber. This excessive stretching of the case at every firing (cumulative damage) makes the brass paper thin, and it soon rips the case apart.

To make it easier to FL resize "accurately" I patented the tool that I use, the Digital Headspace Gauge.



</div></div>

I slightly disagree.

I believe the firing pin impact drives the case forward in the chamber, such that the shoulder is firmly in contact with the chamber. Excessive headspace in thus situation would create a gap between casehead and boltface. Upon ignition and subsequent pressure rise, the portion of the case with no radial suppirt, and no chamber to "bite" into, blows rearward, in exactly the same spot every time, which is why the ring of death is so straight, and not wavy-gravy.

This excessive HS and blowback into the bolt face can/will also flatten primers and cause "ejector marks" to form, even though pressures may not be over the top. </div></div>

I guess I am confused. The OP clearly has been very careful in terms of not introducing excessive headspace since he bump the shoulder back 0.001” – so why would this still happen? Turbo54, I understand your comment about the firing pin pushing the case forward, but your headspace is still only 0.001”?

 

[zuke]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

A picture truely is worth 1000 word's!
Thank's for your posting!

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jlow</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Innovative</div><div class="ubbcode-body">The picture above clearly shows that case head separation begins on the inside of a case.

Case head separations are caused by pushing the shoulder back too far. When this happens, the shoulder gets blasted forward as it fills out the chamber. This excessive stretching of the case at every firing (cumulative damage) makes the brass paper thin, and it soon rips the case apart.

To make it easier to FL resize "accurately" I patented the tool that I use, the Digital Headspace Gauge.



</div></div>

I slightly disagree.

I believe the firing pin impact drives the case forward in the chamber, such that the shoulder is firmly in contact with the chamber. Excessive headspace in thus situation would create a gap between casehead and boltface. Upon ignition and subsequent pressure rise, the portion of the case with no radial suppirt, and no chamber to "bite" into, blows rearward, in exactly the same spot every time, which is why the ring of death is so straight, and not wavy-gravy.

This excessive HS and blowback into the bolt face can/will also flatten primers and cause "ejector marks" to form, even though pressures may not be over the top. </div></div>

I guess I am confused. The OP clearly has been very careful in terms of not introducing excessive headspace since he bump the shoulder back 0.001” – so why would this still happen? Turbo54, I understand your comment about the firing pin pushing the case forward, but your headspace is still only 0.001”? </div></div>


This is a good question.

This evening I dropped off a barrel and bolt to Karl Kampfeld (who I'm fortunate to know, shoot with, and live near), and happened to start talking about this.

What he told me is that without the competition shellholders, that come in small increments of thickness, he has found it nearly impossible to get consistent shoulder bump - that you might set your die for .001 or .0015 bump, but if the press ram isn't camming over, or at least coming up solid on the bittom of the die, you'll tend to get inconsistent results...

I can say my die, when set for .001" bump, does NOT cam over on the press. Also, I've ever noticed my bolt closing force to be inconsistent as well. Some cartridges allow the bolt to close EASY, but sometimes there is some drag. Now that I think more about it, I doubt I have maintained a CONSISTENT .001" bump.

The case I posted pics of is the ONLY one in a lot of almost 500pcs, and I went over them all last night to find more that might be close. Perhaps that case was the unlucky one, where it was getting bumped more than the others...? It's also possible (but unlikely) it was a range pickup piece of brass that somebody else reloaded dozens of times before I got to it.

I'm gonna get a set of competition shellholders and experiment more.

 

[AtOne]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Looks like you have the scrape marks from the bent paper clip on there too.
Thanks for the great picture of it !

 

[jlow]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Thanks turbo54 – that helps a lot.

I think you are right about not being able to produce a consistent 0.001” bump – I have tried and have measure them with a headspace gauge afterward and they do vary some. Still, I aim for 2 since mine is a gas gun and was hoping that the 3-4 thousands bump sometimes that shows up does not end up causing a case head separation, something that I had always attributed to bigger headspace problem (perhaps I am fooling myself – LOL!).

Still, one out of 500pcs is not bad and I of course do the paper clip test religiously so I am not totally scared shitless yet! LOL!

 

[ldevine]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Interesting phenomenon... I caught that bug too. Progressively gets worst going from left to right. I first thought the culpit was shooting wet cases and having pressure spikes. Good to know about the resizing and I'll investigate that too.

 

[jlow]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

“Shooting wet cases and having pressure spikes”, interesting you say this as I had an interesting conversation with my instructor recently about this very thing. He told me that his experience was that the brass from firing wet seems to be no good anymore and we were postulating that there might be a pressure spike. You have any idea as to why this happens?

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jlow</div><div class="ubbcode-body">“Shooting wet cases and having pressure spikes”, interesting you say this as I had an interesting conversation with my instructor recently about this very thing. He told me that his experience was that the brass from firing wet seems to be no good anymore and we were postulating that there might be a pressure spike. You have any idea as to why this happens? </div></div>

I'm pretty sure it isn't a pressure spike, but rather, the casehead getting slammed into the boltface. The water acts as a lubricant, which prevents the case from "biting" into the chamber, thus greatly reducing the axial force (rearward) of the case on the bolt.

I know that when I fire wet cases, my primer pocket loosens up and I get an ejector mark.

That's my theory.

 

[Bigwheels]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

I have several cases that have squiggly lines etched in the side of the cases from water droplets on the case when chambered. I also had higher pressure in those cases as well. I believe the water takes up space in the chamber, thereby increasing pressure & vaporising which eroded the lines in the case walls.

 

[jlow]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Interesting thoughts thanks!

My own theory is a little like Bigwheels although slightly different. I think the water on the outside of the case vaporize and the pressure from it prevent the brass from expanding to full chamber volume, that like cartridge with reduce volume (i.e. 308 LC military brass) affects chamber pressure and thus the pressure spike.

Unfortunately, all we see is the results and so it is hard to tell one from the other. I have not personally experience this, but my instructor who is a very experienced reloader and long range shooter tells me that both he and his friend who he shoots with finds that the brass affected this way no longer shoots true and have to be discarded.

 

[dvdt]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Thanks turbo for taking the time to post this up. I need to do more research on this and get a paper clip.

What happens when you fire a case and there's case head separation ? In other words, if you hadn't caught this, what would've happened the next time it was fired ? (not trying to argue, trying to learn)

Lastly, are you saying in your first two pics that <span style="text-decoration: underline"><span style="font-weight: bold">bo</span>th </span>cases are experiencing case head separation ? Obviously we can see the one you scotchbrited up, what about the second one ?

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dvdt</div><div class="ubbcode-body">Thanks turbo for taking the time to post this up. I need to do more research on this and get a paper clip.

What happens when you fire a case and there's case head separation ? In other words, if you hadn't caught this, what would've happened the next time it was fired ? (not trying to argue, trying to learn)

Lastly, are you saying in your first two pics that <span style="text-decoration: underline"><span style="font-weight: bold">bo</span>th </span>cases are experiencing case head separation ? Obviously we can see the one you scotchbrited up, what about the second one ? </div></div>

If this case had been fired once or twice more, the pressure would have caused the case to rupture, where tge brass is thinnest. That would create a short circuit; the gas could either bust its ass pushing the bullet down the bore, or take an easier path around the bolthead and down the bolt raceway - toward your face. Modern rifles have vent hole(s) through tge side of the receiver, alongside the bolthead (in its most forward position). The idea is to create an easy escape path for the gas to vent AWAY from your face. It usually works well....Ive often wondered how many old time gunmakers had to learn this the hard way...

Be sure your vents are clean! It's easy to get bedding epoxy in them, or some other crud. Thats not good!

Usually the bullet will still make it out of the barrel, though it will be much slower than normal. You'll know something just happened because of the PSSSSSSSSSST and gascloud coming out the vents.

That is best case scenario.

Worst case is a face full of flaming gas at 1000° going 500mph.

The pics I posted are of the same case, cut in half the long way.

Hope this helps.

 

[dvdt]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Thanks for the detailed reply and likely saving me a failure in the future. I'll be checking my brass this weekend.

Any experience/advice with this in a gas gun ?

 

[boltgunluvr]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

One more reason why I don't load hot.

 

[RedGoat]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Thanks for the pictures, makes finding the signs a lot easier when you know exactly what your looking for.

Keep your powder dry,
Goat

 

[patrad]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Thanks for the thread, turbo54. I've been fortunate enough not to have had a case head separation **SO FAR**

. This is the best pic I've seen of one. Great info, and thanks also to those who posted.

Y'all take care.

 

[MtnCreek]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">This is a piece of Lapua 308 brass I've loaded about 8 or 9 times. Hot!! loads of 45.5gr Varget and a 175smk. </div></div>

That's pretty off the chart for Lapua brass. Your probably a couple of grains above normal max pressures, correct?

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MtnCreek</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">This is a piece of Lapua 308 brass I've loaded about 8 or 9 times. Hot!! loads of 45.5gr Varget and a 175smk. </div></div>

That's pretty off the chart for Lapua brass. Your probably a couple of grains above normal max pressures, correct? </div></div>

Hodgdon lists 45gr as max, but I don't remember what brass that is in.

Either way, my load is certainly pretty hot, but with the velocities I get, I don't think pressure is off the charts. My 24" barrel (which was a slow barrel) did 2650fps, and my new 26" barrel does 2750fps.

 

[MtnCreek]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

I wonder if you have a slightly oversized chamber. If you fire formed with a reduced or starting charge, then loaded to your current charge, that could give you additional capacity and reduce pressure. It could also explain short case life, assuming the case stretched a good bit on the initial firing. A slightly oversized chamber could also be the reason for the 'slow barrel'. Your load would lock my bolt up. Either way, thanks for the photos!

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MtnCreek</div><div class="ubbcode-body">I wonder if you have a slightly oversized chamber. If you fire formed with a reduced or starting charge, then loaded to your current charge, that could give you additional capacity and reduce pressure. It could also explain short case life, assuming the case stretched a good bit on the initial firing. A slightly oversized chamber could also be the reason for the 'slow barrel'. Your load would lock my bolt up. Either way, thanks for the photos! </div></div>

Actually, it's a Savage, and HS is less than minimum + .001", though it has a generous neck and throat. My partners custom 308, done by SAC gets 2650fps from 43.2gr Varget though, so something is quite different!

 

[wilecoyote]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jlow</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Innovative</div><div class="ubbcode-body">The picture above clearly shows that case head separation begins on the inside of a case.

Case head separations are caused by pushing the shoulder back too far. When this happens, the shoulder gets blasted forward as it fills out the chamber. This excessive stretching of the case at every firing (cumulative damage) makes the brass paper thin, and it soon rips the case apart.

To make it easier to FL resize "accurately" I patented the tool that I use, the Digital Headspace Gauge.



</div></div>

I slightly disagree.

I believe the firing pin impact drives the case forward in the chamber, such that the shoulder is firmly in contact with the chamber. Excessive headspace in thus situation would create a gap between casehead and boltface. Upon ignition and subsequent pressure rise, the portion of the case with no radial suppirt, and no chamber to "bite" into, blows rearward, in exactly the same spot every time, which is why the ring of death is so straight, and not wavy-gravy.

This excessive HS and blowback into the bolt face can/will also flatten primers and cause "ejector marks" to form, even though pressures may not be over the top. </div></div>

I guess I am confused. The OP clearly has been very careful in terms of not introducing excessive headspace since he bump the shoulder back 0.001&#148; &#150; so why would this still happen? Turbo54, I understand your comment about the firing pin pushing the case forward, but your headspace is still only 0.001&#148;? </div></div>


This is a good question.

This evening I dropped off a barrel and bolt to Karl Kampfeld (who I'm fortunate to know, shoot with, and live near), and happened to start talking about this.

What he told me is that without the competition shellholders, that come in small increments of thickness, he has found it nearly impossible to get consistent shoulder bump - that you might set your die for .001 or .0015 bump, but if the press ram isn't camming over, or at least coming up solid on the bittom of the die, you'll tend to get inconsistent results...

I can say my die, when set for .001" bump, does NOT cam over on the press. Also, I've ever noticed my bolt closing force to be inconsistent as well. Some cartridges allow the bolt to close EASY, but sometimes there is some drag. Now that I think more about it, I doubt I have maintained a CONSISTENT .001" bump.

The case I posted pics of is the ONLY one in a lot of almost 500pcs, and I went over them all last night to find more that might be close. Perhaps that case was the unlucky one, where it was getting bumped more than the others...? It's also possible (but unlikely) it was a range pickup piece of brass that somebody else reloaded dozens of times before I got to it.

I'm gonna get a set of competition shellholders and experiment more.</div></div> At today,with or without comp.dies,with or without comp.shellholders,with or without shim spacers under the die,etc.,if I need be absolutely sure about the amount of bumping,I must measure every single bumped case...after bumping_beside my reloading faults,I think can be unpredictable the amount of real shoulder springing back of every single case,even using the best brands_I hope you can be luckyer...

 

[desertrat1979]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

This is what happens when you dont pay close attention. I was able to snap off the case head with my thumb. Never knew that could happen till I asked about it on here.

 

[WKR]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

Thanks, it's great information and the pictures make it a lot easier to understand, I have been reloading for a few years and didn't know about using the paper clip to look for this signs inside the cases, I have some .223 brass that I have loaded 6 times that will probably show some of this signs. Another reason why it's so important to use eye protection when shooting, I have a friend who doesn't like using eye protection because he thinks it defeats the purpose of the great glass on his Nightforce scope

 

[chavezz556]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

What if we are seeing the line towards the middle of the case ? Is it because of the same reason ? I only have one hot load and it's not even at max (44.8 varget under a nosler 168 @2.810 LC 72 brass) ..... I also don't like using eye pro when shooting rifle ... But I will be looking for some good eye pro soon

 

[Wannashootit]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

OK, so I've only been reloading for a couple of years...
BUT, I don't "get" reloading <span style="font-style: italic">above</span>the maximum load indicated by the manufacturer.

The Hodgdon chart shows this is already a compressed load <span style="font-weight: bold">at 45.0</span> with the 175 SMK- which makes it inherently more dangerous to begin with. Depending on- and variations with- your bullet seating depth could easily push this too far.

Seems to me you're walking a knife edge... loading to achieve a certain velocity, above the manufacturer's limits- without knowing what your chamber pressures are isn't prudent. It would be interesting to have an RSI Pressure Trace on that chamber when you detonate that load...

But like I said, I'm a relative novice- so feel free to correct me.

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Wannashootit</div><div class="ubbcode-body">OK, so I've only been reloading for a couple of years...
BUT, I don't "get" reloading <span style="font-style: italic">above</span>the maximum load indicated by the manufacturer.

The Hodgdon chart shows this is already a compressed load <span style="font-weight: bold">at 45.0</span> with the 175 SMK- which makes it inherently more dangerous to begin with. Depending on- and variations with- your bullet seating depth could easily push this too far.

Seems to me you're walking a knife edge... loading to achieve a certain velocity, above the manufacturer's limits- without knowing what your chamber pressures are isn't prudent. It would be interesting to have an RSI Pressure Trace on that chamber when you detonate that load...

But like I said, I'm a relative novice- so feel free to correct me. </div></div>


This has been argued ad infinitum here, in numerous threads, so I'm not going to even get into it here.

That not withstanding, CHS has little to do with pressure. Even light charges, generating 40ksi WILL cause the case to fill up the chamber. Thus, if you are sizing your brass too small for your chamber, you're going to be stretching the brass and you'll get CHSs, regardless of your charge.

 

[b_4]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

This thread got me thinking about risk vs reward as it pertains to case life. By firing a case twice you have halved your case cost. Three times it is a third and so on. Eventually it begins to go asymptotic and your risk of failure (Case Head Separation) etc begins to go up greatly but your savings increase becomes minimal.

This figure is based upon brass at a simple cost of $50/100 pieces of brass. After five firings the cost of brass per round fired is at $0.10. Doubling the number of times fired to 10 only saves $0.05 per shot.

Quite simply, five firings is a good point to balance rate of return vs risk IMHO.

 

[Wannashootit]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

I got the basics of case separation back when as relates to excessive headspace, lube on the cases, etc.

But 8, 9 loadings- even with Lapua brass, not just "hot"- but beyond "hot", exceeding the manufacturer's load data for what is a compressed load a half-grain less, pressure effects should not be minimized.

You never mentioned whether you trimmed the cases after so many loadings. Would be interesting to know if you did, because certainly those overly hot loads worked even that Lapua brass...

If the cases weren't trimmed, case neck gets jammed into the leade, bullet gets crimped, you know the rest.

I know pressures ALONE are not a major cause of case separation, but you seem to be saying that it's not relevant- and if so, please direct me to the threads that explain why.

I just don't think it's wise to trivialize compressed loads beyond the manufacturer's max.

 

[turbo54]

Re: This is how IMMINENT CASEHEAD SEPARATION looks!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Wannashootit</div><div class="ubbcode-body">I got the basics of case separation back when as relates to excessive headspace, lube on the cases, etc.

But 8, 9 loadings- even with Lapua brass, not just "hot"- but beyond "hot", exceeding the manufacturer's load data for what is a compressed load a half-grain less, pressure effects should not be minimized.

The OP never mentioned that he trimmed the cases after so many loadings. Would be interesting to know if he did, because certainly those overly hot loads worked even that Lapua brass...

If the cases weren't trimmed, case neck gets jammed into the leade, bullet gets crimped, you know the rest.

I know pressures ALONE are not a major cause of case separation, but you seem to be saying that it's not relevant- and if so, please direct me to the threads that explain why.

I just don't think it's wise to trivialize compressed loads beyond the manufacturer's max. </div></div>

Look at the pics again, closely...

You might notice a very nice 60° VLD chamfer on the insides of the casemouth...

You may also notice a nice 45° chamfer on the outside of the casemouth.

A Giraud trimmer is a helluva tool.

Still more, you might also notice the HAZ from annealing...