Hello Everybody. What is the best method for detecting case head separation? I was just reading about the RCBS Case Master Gauging Tool and it says, among other things,that it can detect impending case head separation before obvious lines appear on the outside of the case. Now, I have been looking at my resized .223 remington and I usually get a line close to the case head where my resizing die stops. How can I tell that from impending case head separation? As I understand it, an impending case head separation is a bright line around the case head and I have seen that on some .308 brass that I have reloaded several times and I discard the brass. Will this RCBS tool help? Is it worth it or should I just look for the bright line? I full length resize all my brass. Any help you could give me would be appreciated. Ray
Best method for checking for head separation?
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Pisgah
Member
Easy-peasy. Take a paperclip, straighten it out. Make a small 90-degree bend at one end (small enough to fit in to the case neck). Put the hook down in to the case and drag it back up against the case wall. Do this 2 or 3 times around the circumference of the case. An incipient case head separation will be distinctly felt by the little hook. If it catches at any point during the examination, discard the case. The bright ring that appears on the outside of the case is normal, but that is where you'll feel the beginning separation on the inside of the case before it happens.
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thank you
Thanks, I will try it! So if I do have the bright ring, the case gets discarded, correct?
Thanks, I will try it! So if I do have the bright ring, the case gets discarded, correct?
Below my $100.00 bent paper clip, or my RCBS case mastering gauge. It will tell you how much the case stretches and thins in thousanths of an inch.
Below a Winchester factory loaded .303 British case that stretched and thinned .009 on its first firing.
Below one of the same batch of Winchester cases the third time the case was fired and a partial case head seperation. Note the case thinned and cracked above the area of max case expanshion.
Below .308 cases fired in a brand new Savage rifle, note the bottom chart and when the cases started to stretch and thin.
Below a Winchester factory loaded .303 British case that stretched and thinned .009 on its first firing.
Below one of the same batch of Winchester cases the third time the case was fired and a partial case head seperation. Note the case thinned and cracked above the area of max case expanshion.
Below .308 cases fired in a brand new Savage rifle, note the bottom chart and when the cases started to stretch and thin.
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Wow! Impressive
Wow! Thank you so much for your time and your input! I am impressed. I guess that RCBS case master gauging tool is worth it! I have to watch a video on it. Would I be able to correct runout or is it just a measuring tool? I have an old sinclair catalogue that features the Sinclair concentricity gauge that will also allow me to correct runout. But I dont think it will allow me to measure case wall thickness. I have to think about this.
Below my $100.00 bent paper clip, or my RCBS case mastering gauge. It will tell you how much the case stretches and thins in thousanths of an inch.
Below a Winchester factory loaded .303 British case that stretched and thinned .009 on its first firing.
Below one of the same batch of Winchester cases the third time the case was fired and a partial case head seperation. Note the case thinned and cracked above the area of max case expanshion.
Below .308 cases fired in a brand new Savage rifle, note the bottom chart and when the cases started to stretch and thin.
Wow! Thank you so much for your time and your input! I am impressed. I guess that RCBS case master gauging tool is worth it! I have to watch a video on it. Would I be able to correct runout or is it just a measuring tool? I have an old sinclair catalogue that features the Sinclair concentricity gauge that will also allow me to correct runout. But I dont think it will allow me to measure case wall thickness. I have to think about this.
Update I watched the video
As an update, I watched the youtube video on the RCBS and it will measure the wall thickness and runout but it will not allow me to correct runout. Neither will the Sinclair. The Hornady Ammo concentricity tool and the Precision Reflex run out rig concentricity guage will allow me to correct runout. I dont know if I want to go to all that trouble since i am not shooting a precision bolt rifle but rather an accurized AR15 (Colt MT 6601 with a Krieger barrel) that I used to shoot across the course with. I might still get the RCBS to help avoid the head separation. Depends on my budget. Thank you for your help.
Below my $100.00 bent paper clip, or my RCBS case mastering gauge. It will tell you how much the case stretches and thins in thousanths of an inch.
Below a Winchester factory loaded .303 British case that stretched and thinned .009 on its first firing.
Below one of the same batch of Winchester cases the third time the case was fired and a partial case head seperation. Note the case thinned and cracked above the area of max case expanshion.
Below .308 cases fired in a brand new Savage rifle, note the bottom chart and when the cases started to stretch and thin.
As an update, I watched the youtube video on the RCBS and it will measure the wall thickness and runout but it will not allow me to correct runout. Neither will the Sinclair. The Hornady Ammo concentricity tool and the Precision Reflex run out rig concentricity guage will allow me to correct runout. I dont know if I want to go to all that trouble since i am not shooting a precision bolt rifle but rather an accurized AR15 (Colt MT 6601 with a Krieger barrel) that I used to shoot across the course with. I might still get the RCBS to help avoid the head separation. Depends on my budget. Thank you for your help.
Above 100% true. That's the way most all of us check our rifle cases.
True story. Many years ago I hunted deer with a .243 Remington 700 BDL. I was a lot poorer then. So as long as my 243 cases would hold a primer and bullet i would load them. One evening a buck came out on my left walking about 40 yards away. I shot him and he went down but far from dead. Started to drag off. I jacked out the empty and the next cartridge went in and jammed(stopped). I ejected it and tried to chamber another with the same results. Fortunately I had my Smith 357(66) to finish ther job.
Got home and found the front 3/4 of the case jammed in the chamber. It came out when I pushed a bore brush on a cleaning rod down the barrel. The case was THIN and separated almost in a perfect circle. Checked my other brass with the bent wire trick and threw almost all of them away. That weas nearly 40 years ago. I'm still using the bent wire to check cases to this day.
Well you could always........
look in a mirror.
Sorry......
I just could not resist that one.
Me bad.
look in a mirror.
Sorry......
I just could not resist that one.
Me bad.
WestDivide
Member
On case stretching:
Case stretching/separation is/are caused by excessive headspace in a rifle's chamber. Commercial rifle chambers are built with tolerance specs defined by SAAMI. They can vary by about .010 in. If you get a rifle cut with new reamer, it could have more headspace (and other dimensions) than one cut with a well used reamer. And, the vagaries of the smith's chambering practices and measurements can add to the variances.
So, if you have a 'longer' chamber, a new factory round will stretch, but likely not dangerously. If you full length resize that case, you return it to listed SAAMI specs for that cartridge. Subsequent firings and FL resizing will exacerbate the stretching, eventually causing circumferential separation. The bright ring on case exterior I've found to be hard to evaluate. The noted paper clip method is pretty accurate, you can feel an inner groove while moving the clip down the inner case wall, albeit it takes a little practice to master. Sectioning a few cases will give you known references to help the learning curve.
Such stretching can be mitigated/minimized by using a neck sizing die. While some eschew this practice, and autoloaders often need FL sizing, it significantly reduces brass wear. Partial resizing with a FL die, can approximate neck sizing, but still moves part of the case.
I've experienced case stretching with a few rifles, factory and one custom AI chamber that appears to have been cut too long. I regularly only neck size most cases, save for range pickup brass. Obviously, new brass only needs neck sizing. The 2506AI chamber was likely cut too long. Both the first round (factory) and subsequent reloads showed stretching. I have figured out the problem and solutions, but that's another post.
Save to say, I have 7 firings on the 2506AI brass, with no apparent increase in stretching, checking visually and with the paper clip. I do lightly lube cases for fireforming, ostensibly a NO-NO, but the cases show no stretching and last well. Ackley describes it, and I do it, but I DON'T ADVISE IT for obvious reasons. You'll have to make that decision.
Biged's chart is interesting. I'd guess his gun does not have significant headspace. He didn't see failure for 7 firings. Ed, I'm curious to what you attribute the longevity of the lower listed cases? Brass hardness, wall thickness?
-West
Case stretching/separation is/are caused by excessive headspace in a rifle's chamber. Commercial rifle chambers are built with tolerance specs defined by SAAMI. They can vary by about .010 in. If you get a rifle cut with new reamer, it could have more headspace (and other dimensions) than one cut with a well used reamer. And, the vagaries of the smith's chambering practices and measurements can add to the variances.
So, if you have a 'longer' chamber, a new factory round will stretch, but likely not dangerously. If you full length resize that case, you return it to listed SAAMI specs for that cartridge. Subsequent firings and FL resizing will exacerbate the stretching, eventually causing circumferential separation. The bright ring on case exterior I've found to be hard to evaluate. The noted paper clip method is pretty accurate, you can feel an inner groove while moving the clip down the inner case wall, albeit it takes a little practice to master. Sectioning a few cases will give you known references to help the learning curve.
Such stretching can be mitigated/minimized by using a neck sizing die. While some eschew this practice, and autoloaders often need FL sizing, it significantly reduces brass wear. Partial resizing with a FL die, can approximate neck sizing, but still moves part of the case.
I've experienced case stretching with a few rifles, factory and one custom AI chamber that appears to have been cut too long. I regularly only neck size most cases, save for range pickup brass. Obviously, new brass only needs neck sizing. The 2506AI chamber was likely cut too long. Both the first round (factory) and subsequent reloads showed stretching. I have figured out the problem and solutions, but that's another post.
Save to say, I have 7 firings on the 2506AI brass, with no apparent increase in stretching, checking visually and with the paper clip. I do lightly lube cases for fireforming, ostensibly a NO-NO, but the cases show no stretching and last well. Ackley describes it, and I do it, but I DON'T ADVISE IT for obvious reasons. You'll have to make that decision.
Biged's chart is interesting. I'd guess his gun does not have significant headspace. He didn't see failure for 7 firings. Ed, I'm curious to what you attribute the longevity of the lower listed cases? Brass hardness, wall thickness?
-West
Pisgah
Member
No. You'll get the bright ring on first firing, and it's normal. But it marks the area you need to check inside the case, and if the paperclip hangs up at that spot, chuck the case.
Yes, excessive head space contributes to early failure. I suggest getting a Hornady head space gage and measure a case fired in your gun to obtain a baseline dimension. Then adjust your resizing die to set the shoulder back about .002-.003. That will minimize and stretching.
?????????? You make no sense with that comment.
rockquarry
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The chart is from HANDLOADER magazine; part of one of the very best gun/ handloading articles ever written in my estimation and I've been reading such for almost sixty years. There's far more to this article than brass life, though brass life is certainly important. Perhaps the article is available online.
Sometimes full-length sizing won't have much effect on case life but other times the effect is quick and significant and detrimental to any semblance of brass life. There are many changeable factors involved here, not the least of which are dies and chambers.
What I've found that works best for most most cartridges (belted magnums included) is a partial sizing with a full-length die. Size enough so there is slight to very slight (subjective thing not easily defined, sort of like degree of crimp) resistance when chambering a prepared,sized case.
Every few loadings (4-6) will require a full-length sizing to bring the shoulder back to where it's easy to chamber again, then go back to the partial sizing.
In decades of handloading, I've never seen a need for the RCBS gauge as described above or neck sizing dies, but there are exceptions to everything.
If you have incipient case head separation in just a few firings, problems abound somewhere, but often they can be fixed without professional help.
One note about ARs; I don't know much about these guns and haven't really decided if I like them or not. I have three Colts and full-length sizing is required for the brass and then I run the cases through a gauge. They work perfectly. Less than a full-length size makes my ARs worthless.
Sometimes full-length sizing won't have much effect on case life but other times the effect is quick and significant and detrimental to any semblance of brass life. There are many changeable factors involved here, not the least of which are dies and chambers.
What I've found that works best for most most cartridges (belted magnums included) is a partial sizing with a full-length die. Size enough so there is slight to very slight (subjective thing not easily defined, sort of like degree of crimp) resistance when chambering a prepared,sized case.
Every few loadings (4-6) will require a full-length sizing to bring the shoulder back to where it's easy to chamber again, then go back to the partial sizing.
In decades of handloading, I've never seen a need for the RCBS gauge as described above or neck sizing dies, but there are exceptions to everything.
If you have incipient case head separation in just a few firings, problems abound somewhere, but often they can be fixed without professional help.
One note about ARs; I don't know much about these guns and haven't really decided if I like them or not. I have three Colts and full-length sizing is required for the brass and then I run the cases through a gauge. They work perfectly. Less than a full-length size makes my ARs worthless.
And sometimes it just happens even with new brass, There could be a defect and the case may fail the first time or the second time. I had A LC brass in 5.56 fail the second time it was reloaded, Only one out of a thousand, Even if you check it and feel nothing anything is possible.
For important stuff like hunting or a big time match have some good new brass, For just range brass it will not matter much.
For important stuff like hunting or a big time match have some good new brass, For just range brass it will not matter much.
gwpercle
Member
I use my eyeball and look for the tell-tale line that shows up on the case well before a crack develops .
Once you know what to look for they are easy to spot during case inspection .
I never could feel them on the inside with a paper clip but spotting the mark on a case was a cinch and you should carefully inspect every case before reloading it .
Gary
Once you know what to look for they are easy to spot during case inspection .
I never could feel them on the inside with a paper clip but spotting the mark on a case was a cinch and you should carefully inspect every case before reloading it .
Gary
thank you
Good Information. Thank you for your input. I was a high power service rifle shooter for many years shooting across the course out to 600 yards with iron sights. I started with an accurized M1A and later moved up to a Colt AR15 MT6601. The colt was match tuned with a new 1:7 krieger barrel with a custom cut chamber and a krieger trigger. The chamber is not over sized so that is not a problem with my brass. Before 9/11, our civillian rifle club was allowed to shoot at Camp Bullis, TX and I picked up lots of army range brass. As long as I resized the brass fired in my own rifle, I had no problems with head separation and I could get 5, 6 or 7 reloads. I started noticing the problem when I ran out of my brass and started using the range pickup brass. I use a sinclair carbide primer pocket uniformer on all my brass and I trim all my brass to 1.75 on my Sinclair Ultimate trimmer with a micrometer so I get very uniform brass. As long as I trim the brass to the correct length, they should chamber fine. I will be on the lookout for case head separation. Thank you for your help.
Good Information. Thank you for your input. I was a high power service rifle shooter for many years shooting across the course out to 600 yards with iron sights. I started with an accurized M1A and later moved up to a Colt AR15 MT6601. The colt was match tuned with a new 1:7 krieger barrel with a custom cut chamber and a krieger trigger. The chamber is not over sized so that is not a problem with my brass. Before 9/11, our civillian rifle club was allowed to shoot at Camp Bullis, TX and I picked up lots of army range brass. As long as I resized the brass fired in my own rifle, I had no problems with head separation and I could get 5, 6 or 7 reloads. I started noticing the problem when I ran out of my brass and started using the range pickup brass. I use a sinclair carbide primer pocket uniformer on all my brass and I trim all my brass to 1.75 on my Sinclair Ultimate trimmer with a micrometer so I get very uniform brass. As long as I trim the brass to the correct length, they should chamber fine. I will be on the lookout for case head separation. Thank you for your help.
