What do you think is the problem here...case head seperation

[Aggrofish]

So I had this happen today on 3x fired Hornady brass and it's unsettling. Most of my rifle reloading has been for .308 where I used standard dies RCBS dies. I never turned necks, used an expander ball, and FL sized only bumping the shoulder back .002. I had 500 pieces of LC LR brass that was primed and never fired. All that brass has 5x on it and I only have a few loose primer pockets. It shot a legit .5 MOA consistently although everyone shoots that on the internet these days.


The Old Ghost Thomas Lovell Beddoes

I'm using basically the same standard FL sizing die on the 6.5 creedmoor along with a Redding competition seating die because the micrometer makes this simple. I'm still only bumping shoulders back .002 but apparently I'm overworking the brass so I was thinking about switching to FL bushing dies. Lately it seems like the expander ball requires more force to be pulled out of the case. I can only assume that the neck is getting sized down too much.

I took some measurements: the RCBS FL standard die I'm using sizes the body from .265 to .264. On fired brass the neck is .295 and running it through the die without the expander ball the neck is sized down to .280. The expander ball opens it up to .286 and a loaded Hornady 140 ELDM measures .289. I measure base to shoulder every time I set up the die. I'm a bit perplexed. What do you think?

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[Dooby]

that's pretty tight neck tension. i'm using a FL-Bushing Redding die, and using a .288/.289" bushing. loaded round measures .290/.291"

But not sure how that would cause case head separation...maybe tight neck tension causing more pressure??

have you cleaned your die recently? possibly dirty and more difficult to to pull out of case? Also, if the brass has been worked hardened it may cause more resistance.

Sizing to .280" (OD) seems very tight

 

[Aggrofish]

I scrubbed the barrel recently removing copper to ensure accurate results when testing seating depth today. Only thing I can think is brass is hardened. Maybe I need to anneal every other firing.

 

[Kiba]

The Hornady 6.5 Creedmoor brass isn't the toughest stuff out there, but it shouldn't have a head separation after 5 firings unless your loads are stupid hot... and with Hornady brass the primer pockets will give out long before 5 firings if the loads are that hot. I have some Hornady 6.5 Creedmoor brass that's been through a semi-auto 6 times and it still is OK down at the web (used the paperclip test and also sectioned a couple of cases.) Primer pockets are another matter with that batch.

Your case head condition and primer condition all look good; I don't see any ejector flow/marks and the primers look great. Last batch of *factory* 140 ELD-M ammo I shot left the primer radii pretty flat.

While your FL die definitely oversizes the neck before expanding it back out, that won't cause a case head separation. The repeated oversizing and expanding will work harden the necks over time, that might be what you're feeling when the expander passes through the neck. Annealing would help that, better yet would be a neck honed or bushing die to minimize neck sizing.

How are you measuring your 0.002" setback? If using bump gauges, what brand?

Reason I ask is I had a similar "oops" myself several years ago where a friend's 22-250 that I was reloading had a couple near head separations after only 3 firings. I was using the Sinclair bump gauges with the tapered shoulder to measure the FL sizing. I didn't realize it at the time, but the ID in the Sinclair bump gauge was too small and was contacting the radius where the neck meets the shoulder and not the shoulder itself-- so the readings were bad. What the Sinclair gauge said was 0.002" setback after being FL sized, a Hornady bump gauge said was 0.009-0.011" setback... no wonder the brass failed so fast. I'm still using the Sinclair gauges, but on many of them I've had to open up the ID to clear the radius of the neck/shoulder junction on the case. Proper neck radius clearance is something I check for very carefully now with the Sinclair gauges and I also keep a set of Hornady bump gauges on hand for a verification.

 

[Aggrofish]

This was the 3rd firing on the brass. I just mentioned I'm using the same technique I've used to load 2500+ rounds in my .308 without issue. The .308 has 5 loads on it with zero issues.

I'm using the Hornady headspace gauge. I prefer the RCBS precision mic that I use for other calibers but they didn't make one when I bought the rifle. Primers are all tight, not flattened, and no ejector marks. Bolt opens easily. The only other issue I see is that with new brass the shoulder expands from about 2.251 to 2.256. It stays at 2.256 on every subsequent firing with me setting it back to 2.254 - sometimes 2.253 because sometimes I just can't get it exact.

Today's load was 41.6 of IMR 4451 with 140 ELDMs, fed 210m primers. Previous firing was 42.2. Hotter but still no flattened primers or pressure signs.

The Hornady 6.5 Creedmoor brass isn't the toughest stuff out there, but it shouldn't have a head separation after 5 firings unless your loads are stupid hot... and with Hornady brass the primer pockets will give out long before 5 firings if the loads are that hot. I have some Hornady 6.5 Creedmoor brass that's been through a semi-auto 6 times and it still is OK down at the web (used the paperclip test and also sectioned a couple of cases.) Primer pockets are another matter with that batch.

Your case head condition and primer condition all look good; I don't see any ejector flow/marks and the primers look great. Last batch of *factory* 140 ELD-M ammo I shot left the primer radii pretty flat.

While your FL die definitely oversizes the neck before expanding it back out, that won't cause a case head separation. The repeated oversizing and expanding will work harden the necks over time, that might be what you're feeling when the expander passes through the neck. Annealing would help that, better yet would be a neck honed or bushing die to minimize neck sizing.

How are you measuring your 0.002" setback? If using bump gauges, what brand?

Reason I ask is I had a similar "oops" myself several years ago where a friend's 22-250 that I was reloading had a couple near head separations after only 3 firings. I was using the Sinclair bump gauges with the tapered shoulder to measure the FL sizing. I didn't realize it at the time, but the ID in the Sinclair bump gauge was too small and was contacting the radius where the neck meets the shoulder and not the shoulder itself-- so the readings were bad. What the Sinclair gauge said was 0.002" setback after being FL sized, a Hornady bump gauge said was 0.009-0.011" setback... no wonder the brass failed so fast. I'm still using the Sinclair gauges, but on many of them I've had to open up the ID to clear the radius of the neck/shoulder junction on the case. Proper neck radius clearance is something I check for very carefully now with the Sinclair gauges and I also keep a set of Hornady bump gauges on hand for a verification.

 

[Aggrofish]

Is that Hornady brass? I'm about to order the Redding die and the resident pro on another forum said I should start with the .286 giving me the same neck tension I have now.

that's pretty tight neck tension. i'm using a FL-Bushing Redding die, and using a .288/.289" bushing. loaded round measures .290/.291"

But not sure how that would cause case head separation...maybe tight neck tension causing more pressure??

have you cleaned your die recently? possibly dirty and more difficult to to pull out of case? Also, if the brass has been worked hardened it may cause more resistance.

Sizing to .280" (OD) seems very tight

 

[MarinePMI]

Lately it seems like the expander ball requires more force to be pulled out of the case. I can only assume that the neck is getting sized down too much.

If your expander ball has become loose (unthreaded itself slightly from the rod), you'd feel a pronounced difference when sizing your cases (as well as a some inconsistent neck tension).

 

[Supersubes]

You can buy the bushing die to sort out the necks being worked so much.


Regarding the case head separation, those are always caused by excessive headspace. What kind of rifle do you have?

 

[Gunfighter14e2]

OP, your issue is your over working the brass when resizing. Your chamber is much larger than the die your resizing with.

 

[pmclaine]

Get out your dremel and cut a couple of those cases longitudinally and see if you can view where the web is weakening.

I'd suspect gunfighters supposition is right. Over sizing is easy to do.

Use a Hornady headspace gauge or even an RCBS mic die and check your sizing in relation to SAAMI.

Confirm the measurement of both on a go gauge.

 

[pmclaine]

Are you cleaning with stainless pins?

If I clean with corn cob the expander ball is smooth pulling through the necks.

If I have pin cleaned brass the expander ball sucks and totally screws up my progressive process.

 

[918v]

Maybe it’s your method of checking shoulder bump? Why don’t you use an inverted 40 or 9mm case to measure the shoulder instead. Compare the results.

 

[427Cobra]

It’s the brass, the only true cure is not to use Hornady brass

 

[Aggrofish]

To answer questions:
1.) I'm a tumbler kinda guy - stainless gets everything too clean. I generally don't lube necks because I don't have to.
2.) I'm using the Hornady headspace gauge to measure the setback in the neck. Again only .002. Fired case from base to datum come in at 1.556, I set back to 1.554 or 1.553 if I miss the adjustment slightly.
3.) I'll be getting a RCBS precision mic that they didn't have when I initially bought the rifle. I use that in all other calibers. I think it's probably more accurate than the Hornady kit.
4.) rifle is a factory RPR with 500 rounds through it.

I have to be overworking the brass but I dont think it's in bumping the shoulder back, but maybe it is. I'd rather the problem be me than the brass because I have 200 fired pieces and 300 unloaded. This happened yesterday testing seating depth with a load of 41.6g IMR 4451, 140 ELDM, and fed 210M primers.

ETA this Ruger RPR seems to have a much larger chamber than the 3 savages that preceded it. I still have a .308 stealth and a 338LM HS precision although I haven't loaded for the 338 yet.

 

[Supersubes]

To answer questions:
1.) I'm a tumbler kinda guy - stainless gets everything too clean. I generally don't lube necks because I don't have to.
2.) I'm using the Hornady headspace gauge to measure the setback in the neck. Again only .002. Fired case from base to datum come in at 1.556, I set back to 1.554 or 1.553 if I miss the adjustment slightly.
3.) I'll be getting a RCBS precision mic that they didn't have when I initially bought the rifle. I use that in all other calibers. I think it's probably more accurate than the Hornady kit.
4.) rifle is a factory RPR with 500 rounds through it.

I have to be overworking the brass but I dont think it's in bumping the shoulder back, but maybe it is. I'd rather the problem be me than the brass because I have 200 fired pieces and 300 unloaded. This happened yesterday testing seating depth with a load of 41.6g IMR 4451, 140 ELDM, and fed 210M primers.

ETA this Ruger RPR seems to have a much larger chamber than the 3 savages that preceded it. I still have a .308 stealth and a 338LM HS precision although I haven't loaded for the 338 yet.

Which Hornady comparator are you using? Those numbers look way long. With a .400, a creedmoor go gauge is 1.533” or thereabouts. Regardless of how you’re getting there(short ammo, long chamber, or both) too much headspace is what’s causing the separations.

 

[Aggrofish]

I'll check when I get home later. It's possible that I'm using the wrong comparator, but with the same one I get 1.551 with factory ammo...maybe thats the issue.

 

[pmclaine]

I like RCBS precision mics because they dont tell you anything.

Well I mean they dont tell you any numbers.

If the thing is calibrated right 0 is SAAMI spec.

Than from there the numbers only tell you if you are plus or minus SAAMI spec.

I decided SAAMI must have mae a spec for reason so I decided to set my dies up to go for as close as I could get to 0 on the RCBS.

Is that the best sizing for my chamber likely not but it will work.

 

[Aggrofish]

I checked my notes and Hornady was recommending using the .375 insert. I get different number but the same net result. An unfired case is 1.532.5 and fired is 1.537.5 same .005 stretch when fired.

The real question is how much setback is too much?

Which Hornady comparator are you using? Those numbers look way long. With a .400, a creedmoor go gauge is 1.533” or thereabouts. Regardless of how you’re getting there(short ammo, long chamber, or both) too much headspace is what’s causing the separations.

 

[Supersubes]

I checked my notes and Hornady was recommending using the .375 insert. I get different number but the same net result. An unfired case is 1.532.5 and fired is 1.537.5 same .005 stretch when fired.

The real question is how much setback is too much?

Any chance your fired cases aren’t expanding
fully? Soft loads won’t always come out exactly chamber sized, or will spring back slightly. Back your die off a few thousandths and size a case so it grows slightly(shoulder of die not touching the case shoulder) to ~1.538”. Then see if it chambers. Id remove the striker assembly from the bolt for this. No need to remove the ejector.

 

[Aggrofish]

thats a possibility. I'm tossing the rest of the 2x fired brass and will test the next batch to see if they stretch further beyond the first firing. I think I'll just run a mandrel expander through after the first firing and not touch the shoulder at all since they chamber fine

 

[Sheldon N]

0.005 shoulder bump is way to much sizing and will lead to case head separations as you've found. I like to bump just enough to get easy bolt close, which is between 0.0015 and 0.002 back from a piece of brass that has fully expanded from either multiple firings or a hotter load. If your unsized brass was chambering fine and you've been bumping back further from that number then you've definitely been pushing the shoulder back too far.

Not sure what action you're running, but if you can pull the firing pin spring and any ejector plunger you'll be able to feel exactly how much resistance the brass gives on bolt close.

 

[Gunfighter14e2]

Shoulder bump has nothing to do with your issue. Your problem is the chamber diameter is much larger than your resizing die. You are over working the base, much like firing ammo in NATO chamber then resizing with a small base die. Cast the chamber an your resizing die, measure both, it will be very evident.

 

[Aggrofish]

The brass stretches from unfired to fired ( base to datum) .005, im only bumping the shoulder back .002 AFTER FIRING when I FL size. I'm not bumping the shoulder back from unfired brass. I was saying 1x fired, unsized brass chambers fine. Thus on this next batch on the first firing I'm not going to bump the shoulder at all.

0.005 shoulder bump is way to much sizing and will lead to case head separations as you've found. I like to bump just enough to get easy bolt close, which is between 0.0015 and 0.002 back from a piece of brass that has fully expanded from either multiple firings or a hotter load. If your unsized brass was chambering fine and you've been bumping back further from that number then you've definitely been pushing the shoulder back too far.

Not sure what action you're running, but if you can pull the firing pin spring and any ejector plunger you'll be able to feel exactly how much resistance the brass gives on bolt close.

 

[culater]

Break down and buy Lapua brass and be done with it.

 

[Deleted member 10043]

It's not because he is using hornady brass and telling him so is bullshit.

 

[918v]

OP:

How much is your brass expanding a quarter inch north of the case head? I have a bunch of 1x range brass that expanded between .469” and .471”. What does it measure after you size it?

 

[918v]

Also, section the case that cracked and see if it thinned out in the area of the crack or just cracked due to a defect.

 

[Aggrofish]

Unfired brass - .464
Fired - .469
Sized .466

Not isolated I was starting see rings around other brass. But I'll cut one tomorrow my Dremel is at my work.

OP:

How much is your brass expanding a quarter inch north of the case head? I have a bunch of 1x range brass that expanded between .469” and .471”. What does it measure after you size it?

 

[Dooby]

Is that Hornady brass? I'm about to order the Redding die and the resident pro on another forum said I should start with the .286 giving me the same neck tension I have now.

Yes, Hornady Brass. I also use the same for my Norma brass.

I find that putting the case head end to the LED flashlight of your phone, carefully looking through the neck, you can see the inside of the case pretty good. Use a paper clip to confirm there's no ring developing inside.

 

[918v]

Unfired brass - .464
Fired - .469
Sized .466

Not isolated I was starting see rings around other brass. But I'll cut one tomorrow my Dremel is at my work.
View attachment 6927240

Then it’s not your chamber being too big or your die overworking your case. It is prolly an error in your measuring and in your die adjustment.

 

[Gunfighter14e2]

It's a pressure cut an over resizing, nothing more. Take a piece of wire cut it 45* then bend it a short 90* to get threw the neck. Push it up an down the inside of the brass an you will feel it. Knowing what to look for on the outside of the brass save time. This issue is as old as time with re-loaders.
If you investigate you will find the ring is right at the end of the chamber an is not supported by same. Now add slight over pressure an over sizing an there is not a mfg of brass made that will not do this, fact!

 

[pmclaine]

The paper clip trick is good.

I keep that tool on my reloading bench and check brass.

At present my oldest brass is 5X fired KA (Korean) 73, 30-06. Still no signs of the split with the paper clip.

Before I load this for its 6th time I'll section a piece of brass in half and I'm guessing I'll se a thinning of the brass at the top of the case head.

When people speak of "brass growing" and the requirement to trim this is why.

The brass you trim has to come from somewhere and over time it's the stretch at the case head.

Reload right it's gradual and can happen only after many firings.

Over size or have a messed up chamber stand by for a case head separation much sooner than you would have expect.

 

[MountainHunter]

Oh boy my dumb ass got to deal with this for the first time this weekend. I was shooting the PRS match in Cody while it happened, sucked pretty bad but could have been worse. I had 2 complete case head separations during day 1 so I pulled out the really bad looking cases and luckily didn't have another separation on day 2. I never had it happen before so was pretty perplexed when it happened. Luckily a couple of good fella's out of Colorado helped me get the stuck cases out so I could keep shooting.

6.5 Creedmoor, prime brass between 3 & 4 loadings on all the brass, 140 ELD's, 40.9 grains of H4350. I have a Whidden die and shoulder bump gauge but I was measuring it with a piece of shit caliper from Home Depot or Harbor Freight or some such place and I was obviously over working it. I ordered one of the Mitutoyo's from Amazon so I can check how much I was actually bumping the shoulder once it gets here.

Here's a piece of brass I cut.





Pretty obvious to me now but I had no idea before it happened.

 

[Aggrofish]

The ring is obvious but I have a hard time detecting anything with a paper clip. Maybe sharpening it to a point would help.

 

[Gunfighter14e2]

The ring is obvious but I have a hard time detecting anything with a paper clip. Maybe sharpening it to a point would help.

cut the tips to a 45* angle then make sure the tip of the angle is up.

 

[Killswitch Engage]

are you by chance measuring your fired brass with the old primer still in the case? if so you can get erroneous measurements by a few thousands doing that and then be excessively bumping the shoulder and not realizing it.

 

[918v]

The paperclip method is tedious and imprecise. You can spend a whole afternoon and learn nothing. HS can be detected by looking closely at the case wall at an angle to a light source. You look for a shiny mark, a ring, and then you look real close to see if the ring is also a depression just like on the inside. It’s gonna be much less pronounced, maybe 5% of what the inside looks like, but it will be there.

 

[Precision Underground]

I only bump the shoulder after a few firings when I can feel resistance when the bolt closes, otherwise it is neck sizing only. When I do bump the shoulder I don't measure anything. I take a piece of brass with resistance and size it slightly little by little chambering it each time to see if the resistance is gone. Then there is no question as to how the chamber and the method of measuring the bump line up. Chamber the first 5-8 sized pieces after getting the die set to make sure it is correct and then go to town. The error between how the bump is measured and how the brass actually sits in the chamber is usually much greater than .002.

 

[MarinePMI]

A Hornady headspace comparator is worth it's weight in gold to prevent over bumping the shoulder. Just tossing that out there....

 

[morganlamprecht]

Any chance your fired cases aren’t expanding
fully? Soft loads won’t always come out exactly chamber sized, or will spring back slightly. Back your die off a few thousandths and size a case so it grows slightly(shoulder of die not touching the case shoulder) to ~1.538”. Then see if it chambers. Id remove the striker assembly from the bolt for this. No need to remove the ejector.

this would be my bet...happened to 2 of my buddies. they fired once and the brass wasnt fully formed...they measured everything and set up dies then started splitting cases on the 3-4 reload

 

[MarinePMI]

This ^^^^

40.9 grains of H4350 for a 140 is a pretty light charge...

 

[Greg Langelius *]

Light charge or heavy, the case will fully expand to fill the chamber. If the resizing die is adjusted too close to the shell holder, it will shorten the shoulder height too far.

When the paperclip test tells me I'm getting case wall thinning down just above the web, the first thing I do is to adjust the die a half turn higher, away from the shell holder/shell plate, and toss the brass, it's already screwed beyond retrieval.

We can argue and bicker for weeks over what test works and what may be the cause. The solution is almost always the same; decrease the amount the case gets sized.

If it's the wrong solution, it will become immediately obvious when the case resists bolt closure, and no harm will be done.

Sheesh people, just fix it. Just cut to the chase.

If it's the right solution, but the adjustment wasn't enough, the paperclip test will reveal that, too.

Listen to GF14E2; he's got the right info.

This is one reason why I use the 260 instead of the 6.5CM. If my 260 case needs bumping, I just pull the decapper stem out of my 308 die and run the 260 case through it. You can't do this with the 6.5CM because there's no other case that corresponds to it like the .308 does to the .260. This is one key reason why I returned to shooting the 308, so I would have the dies for doing other things, like this. It bumps the case without working the neck, which is what I have the 260 resizing die already set up to do. This way, I never need to touch my 260 resizer die setup.

I have my basic 260 F/L resizer die set up high, so it only partially neck sizes, and I make my 260 brass from 7mm-08 brass (Hornady). This leaves the aft end of the neck at 7mm, which fits in the SAAMI 260 chamber just fine, and perfectly centers the case neck in the neck/throat of the chamber, thus automatically controlling runout (by centering the rear of the projectile as it's entering the rifling). It also completely seals the neck during firing, NO carbon gets past the end portion of the resized case neck.

But it also does nothing to set back the shoulder if it's needed. Hence the 308 F/L die for the bump. I know when the bump is needed when the resized case chambers hard.

Both my .260 and .308 dies are set up so the case fits perfectly in a 308 case length gauge, and not according to any chamber. If the chamber does not fit, they are Savage rifles, and I reset the barrel for better headspace. So I don't chase the barrel, I chase the gauge. I don't set the case up to match the chamber, I set the barrel up so it works right with a case that perfectly fits the gauge. That's the way you get the most out of a SAAMI chamber.

Listen to me, don't listen to me; it's all good. But remember, I've had going on 25 years of handloading experience in which to develop my own techniques, and the ones I have developed are all for specific reasons.

One thing nobody is talking about here is that it's not just the case that stretches; at 60,000-ish PSI, the chamber is also stretching. It's this stretch and recontraction during the firing which is causing the case to thin out. If the case starts out too short, it stretches more, and that's when the damage is being done. My headspace is set up so that there's always a small degree of bolt drag on closure, indicating minimal headspace.

This is also another really good reason why hot loading is dumb. Get that load hot enough, and there's no headspace adjustment that can save your brass, and I'm not just talking about the primer pockets.

Look up "incipient case head separation". It's not like there's no information on this subject.

Done.

Greg

 

[Supersubes]

Light charge or heavy, the case will fully expand to fill the chamber. If the resizing die is adjusted too close to the shell holder, it will shorten the shoulder height too far.

When the paperclip test tells me I'm getting case wall thinning down just above the web, the first thing I do is to adjust the die a half turn higher, away from the shell holder/shell plate, and toss the brass, it's already screwed beyond retrieval.

We can argue and bicker for weeks over what test works and what may be the cause. The solution is almost always the same; decrease the amount the case gets sized.

If it's the wrong solution, it will become immediately obvious when the case resists bolt closure, and no harm will be done.

Sheesh people, just fix it.

If it's the right solution, but the adjustment wasn't enough, the paperclip test will reveal that, too.

Listen to GF14E2; he's got the right info.

This is one reason why I use the 260 instead of the 6.5CM. If my 260 case needs bumping, I just pull the decapper stem out of my 308 die and run the 260 case through it. This is one key reason why I returned to shooting the 308, so I would have the dies for doing other things, like this. It bumps the case without touching the neck, which is what I have the 260 resizing die already set up to do. I never need to touch my 260 resizer die setup.

I have my basic 260 F/L resizer die set up high, so it only partially neck sizes, and I make my 260 brass from 7mm-08 brass (Hornady). This leaves the aft end of the neck at 7mm, which fits in the SAAMI 260 chamber just fine, and perfectly centers the case neck in the neck/throat of the chamber, thus automatically controlling runout (by centering the rear of the projectile as it's entering the rifling). It also completely seals the neck during firing, NO carbon gets past the end portion of the resized case neck.

But it also does nothing to set back the shoulder if it's needed. Hence the 308 F/L die for the bump. I know when the bump is needed when the resized case chambers hard.

Both my .260 and .308 dies are set up so the case fits perfectly in a 308 case length gauge, and not according to any chamber. If the chamber does not fit, they are Savage rifles, and I reset the barrel for better headspace. So I don't chase the barrel, I chase the gauge. I don't set the case up to match the chamber, I set the barrel up so it works right with a case that perfectly fits the gauge. That's the way you get the most out of a SAAMI chamber.

Listen to me, don't listen to me; it's all good. But remember, I've had going on 25 years of handloading experience in which to develop my own techniques, and the ones I have developed are all for specific reasons.

One thing nobody is talking about here is that it's not just the case that stretches; at 60,000-ish PSI, the chamber is also stretching. It's this stretch and recontraction during the firing which is causing the case to thin out. If the case starts out too short, it stretches more, and that's when the damage is being done. My headspace is set up so that there's always a small degree of bolt drag on closure, indicating minimal headspace.

Done. Look up "incipient case head separation".

Greg

Greg, gunfighter disagrees with you on the cause. He believes it’s oversizing at the base(diameter), not a headspace dimension issue like you me and the rest of the posters believe.

 

[Aggrofish]

Appreciate the feedback and suggestions. The only thing I can contribute this to is the expander ball being a little loose adding additional stress on the upstroke or a slightly incorrect measurement on the Hornady gauge. Solution: I picked up an RCBS precision mic for 6.5, a universal decapping die to make sure I'm measuring without any primers and a new set of Redding S FL bushing dies to possibly better control neck sizing.

 

[Precision Underground]

Appreciate the feedback and suggestions. The only thing I can contribute this to is the expander ball being a little loose adding additional stress on the upstroke or a slightly incorrect measurement on the Hornady gauge. Solution: I picked up an RCBS precision mic for 6.5, a universal decapping die to make sure I'm measuring without any primers and a new set of Redding S FL bushing dies to possibly better control neck sizing.

Use your chamber to measure and there will be no question as to the headspace.

 

[MountainHunter]

As a follow up to my issue, I got my new caliper in and measured a bunch of fired cases to my sized cases I had leftover. I was bumping my shoulder almost 10 thousandths!!

I guess there’s no question to where the case head separations were comng from.

 

[Aggrofish]

At least you know. I measured with the precision mic and it was pretty dead on with the Hornady gauge.

As a follow up to my issue, I got my new caliper in and measured a bunch of fired cases to my sized cases I had leftover. I was bumping my shoulder almost 10 thousandths!!

I guess there’s no question to where the case head separations were comng from.

 

[Greg Langelius *]

Supersubes, I revisited your post and agree with you completely: I got your post wrong the first time around.

I believe the best brass is the brass that gets worked the least.

Essentially, by backing off my F/L die, I'm reducing brass lower sidewall working to about none. Like the rearmost portion of my necks, left at 7mm, the lower sidewalls are left at their expanded dimensions, and little or no further working occurs. I had expected resistance when chambering, but that does not occur. In the process, case length growth also appears to have largely disappeared. In essence, the chamber expansion and contraction may be doing most of the case resizing on its own; with my F/L die mostly just resizing the end portion of the neck.

When I bump, it's with a SAAMI 308 F/L die that has no internal parts mounted. On the latest set of Hornady brass, three reloadings in, there's still no resistance to chambering; so no bumps yet.

So, effectively, GF14's view about base resizing would also appear to be supported by my own case prep process.

I also avoid the hotter end of the charge weight range, and believe this reduces 'wear' on the primer pockets, the other nearly only source for case degradation.

When my cases become unusable, it's essentially from neck splits, and I haven't actually seen one in years.

Greg

 

[Geno C.]

We haven't gotten an answer at to whether he is measuring with the primer still in or not. That is important. Every single time I have seen this it is tracked down to excessive sizing and too much headspace. Every single time.

Take a single piece of brass and load and shoot it. You said after firing and before sizing that they chamber just fine. That's a sign that they are not fully formed to the chamber.

Now neck size only and fire again. Check if it'll chamber again. If there is resistance; then pop the primer and measure your base to shoulder datum. Measure your bump from there.

If there is still no resistance when you chamber before resizing then repeat the load and shoot until there is.

 

[Praeger]

Germán A. Salazar wrote a useful article in the Riflemans Journal in 2010 relating to case head separation.

https://web.archive.org/web/2013111.../2010/05/reloading-case-head-separations.html