Incipient Case Head Separation

[coloradokevin]

After reloading for quite a few years, and many thousands of rounds, I today encountered what I believe is incipient case head separation for the first time. I've worn out a number of pieces of brass in the past, and most of my rifle cases seem to give up at around 8 loadings or so, usually due to loose primer pockets or splitting necks.

This is the first time I've seen cases show signs of an imminent case head separation, and it was on my .260 Remington (using Lapua brass). What baffles me is that this problem occurred with only five loads on the brass, while running a relatively moderate load (140 grain bullet at 2717 fps). Given Lapua's reputation for long brass life, and the great expense of this brass, I'm a bit disappointed to see it failing already. This rifle also has a fairly tight chamber, so I can't see this being a excessive headspace issue with the rifle.


Nevertheless, it raises a few questions for me:


1) How do I increase brass life to avoid encountering this problem for a few extra loadings in the future?

2) Should I discard the remaining loaded ammo? Should I discard the other cases that don't show this problem? NOTE: I didn't notice this issue until I was picking up brass after shooting about half of my loaded ammo. The problem was visible on about 5 cases of 25 or so that I fired, and consisted of a slight groove around the base of the case (in a ring). If I diagnosed this correctly, those pieces are very near failure, and obviously can't be loaded again.

 

[bob4]

All though I'm not experienced enough to answer your question on longevity of the brass I am curious. That's a pretty significant looking ring. Did you run a clip down the inside to feel the groove?
I probably wouldn't discard the cases that don't show this problem. But if it started on other cases on the next load I might.

 

[Walkalong]

The one case looks like it may have a stretch mark down low, nothing to worry about if that is what it is, and another line up higher that concerns me. The only way to tell for sure is to check the cases internally.

See if this helps, it answers the question as to why and how to keep case stretching to a minimum.

http://www.thehighroad.org/showthread.php?t=734058

 

[lysanderxiii]

(1) has been answered.

(2) Take a sample of the lot and check with a paper clip, if a high enough percentage have internal thinning, scrap, if they don't keep.

 

[coloradokevin]

I should have mentioned that I already did the paperclip test on this brass… I've always kept a bent paperclip on the loading bench to check brass for this purpose, I've just never had brass give me the "ring" before it has given out in some other way. Anyway, most of the pieces with the "ring" seem to have thinning at about that point on the inside.

The cases I've checked so far that do not have the ring feel smooth inside, like they should.


So, about the shoulder push-back, what technique do you guys use to set your sizing die to minimize setback? I run Lee dies, because they've always done a good job for me, and my setup technique for these dies (even on my competition rifles) has always involved simply following the instructions that came with the dies in the box. I know that's a rather neanderthal technique compared to what some of you probably do, but I've always done it that way because it's always worked for me in the past (the old 'if it ain't broke, don't fix it').

On my .308 Win I neck sized the brass, and would typically only FL size when extraction became more difficult. On the .260 Rem I found that neck sizing was always tight in that gun, so I've only FL sized this batch of Lapua brass.

 

[coloradokevin]

Actually, I just realized that the "bump gauge" I have for my .308 Win should also work on the .260 Rem, since they're the same parent case. I've never really played with it much, simply because my loading process (as used with my other rifles) has always given me what I looked for.

The video associated with this link on Sinclair's site seems to describe how to set things up as you guys mentioned (to minimally work the brass). Presumably this is what you guys were talking about:

http://www.sinclairintl.com/reloadi...ools/sinclair-bump-gage-insert-prod35265.aspx


Do you suspect that doing this will provide me with noticeably longer brass life?

Again, I'm finding myself at a point where I'm trying to fix a problem that I haven't seen develop with my other rifles. Using basic die setup techniques I'm at 9+ firings on many of my .308 pieces, and they're about to be discarded due to loose primer pockets. Almost all of my brass for the .260 is between 4 and 5 firings right now, so I'm thinking that I'm going to start to see more of this… if I need to buy new Lapua brass (at approximately $1/piece) I sure want to get more than 5 loads from it!

Thanks again!

 

[GW Staar]

You haven't mentioned what rifle you are shooting this ammo in. If it is a semi-auto AR-10 or clone then those Lee dies may be bumping the shoulders as much as .007" or .008" That leaves a lot of room to move forward then backward to the bolt face. That would be the first thing I'd check. Military cut chambers are longer usually, but probably not in .260, that being only a commercial cartridge.

I have personally had to deal with this loading for my .308 Remington R25. If you are not shooting an AR clone disregard the following:

If too much shoulder bump is happening, you will want to back off the sizer a bunch, to make it bump .002 or .003 as Walkalong mentioned.

The caveat in doing that is that the "tight" chamber you mention may not size the brass enough at the base to allow the bolt to close easily to feed and re-feed reliably out of a semi-auto magzine.

If that happens, it brings to the forefront the classic need for a small-based sizer..........which allows you to bump way less and still size the base small enough to be reliable.

One more thing: Some Small-based sizers bump a .001" more than a regular sizer.....some don't. A little research to find one that doesn't........but still .001" isn't .007" and you can still back off the dies and you still size the base circumference one or two thousandths more than a regular sizer relatively. (relative to the distance between the shell holder and the die's bottom surface)

 

[coloradokevin]

Sorry, meant to put it in the opening post. I'm shooting an Accuracy International AX rifle (bolt action).

 

[gamestalker]

The other step is to make sure you aren't bumping the shoulders more than necessary. But if your chamber is larger than the die, over working of the brass down where case head separation occurs will still be a problem for you.

Measure the OD of the fired brass just above the line, then measure it again after resizing. The variance is how much the brass is getting worked during sizing.

Have you tried intermittently neck sizing, it might help extend the life of the brass a little?

GS

 

[Clint M]

This is by far the best way I have found to size brass correctly without over working. Hornady Comparator set with headspace bushing, you can also use it to set your bullet seating depth it work great for both. Measure a fired case from your rifle with the Hornady Comparator using correct headspace bushing, set your full length sizing die to size the case moving the shoulder back .002". This works, it does not over size brass, and you should have no problem chambering brass either, however some people do size less with bolt action you can play with sizing less if you want to however case life will not vary much if any from setting the shoulder back .002"

I would buy the set if you have several cartridges read over the instructions etc the 308 bushing insert will work with many cartridges.. the bullet insert bushings make life just as easy and handloading so much easier.

 

[WestKentucky]

Not trying to derail the thread, but having always caught this before it happens, I'm curious to know what the consequence would be should a case actually fail in the firearm. It would have already built pressure so I'm assuming it would not blow back through the action, but would the separated piece stick? Would it spring back to a normal size and simply fall out with a gentle shake or perhaps a nudge from a cleaning jag?

 

[243winxb]

New brass may be damaged on the first firing as it stretches to fill the chamber. The new brass, when measured from head to datum, may be a lot shorter than an in spec chamber. Most times, this is not a problem till brass has to stretch more than .015" A head separation has different results, depending on the action used. A Rem 700 type is safest. A Savage may blow the extractor out of the bolt. An Auto type will have damage.

 

[Clint M]

Most if not all receivers have safety device as simple as the small holes in a Remington (and most if not all other bolt actions) that vent gases in case of a head separation. Autos also have built in safety vents magazine well acts as a vent if enough gas it will blow magazine out venting gas down away from face. This is just a couple of example you can do a google search that shows pictures that explain it much better than I can.

I have seen case head separations in bolt guns where the broken piece (neck) gets removed when the next round does not chamber completely by removing the round your trying to chamber LOL. Autos same way, sometimes the case neck that has broken really sticks and you may have to use a brass rod or wooden rod to bump it out from the muzzle end.

10/22's do not have any safe way to vent gases (blowback action) I had a 17hmr fire out of battery which sent brass, powder all over my face (glad I had my safety glasses on) powder went between my glasses and face and also burned my eye. No major damage however years later I had a cancerous bump removed that was brass coming out of my face, I still to this day have brass bits that come to the top of my skin which I will dig out once it makes a knot.

I told the above story just to let you know this is not something to "see if I can get one more shooting from" it's just not worth it. The 17hmr is wimpy compared to centerfire ammo even tho all ( I can't think of any without) new centerfire rifles have to lock into battery to fire while having a system to vent gasses in case of problems.

The 17hmr case ruptured in a 10/22 mag I was testing 3 barrels from different manufactures when Hornady released 17hmr (before release of 17hmr)along with another guy. This was not the fault of anyone other than myself.

 

[GLOOB]

IMO casehead separations are often a non issue, as far as the gun is concerned. Obviously, I would adjust my sizing operation to make it stop happening, but I wouldn't pull down my already loaded ammo. I would shoot it.

Pierced primers will erode away the firing pin and cut a little gas ring on the breechface, because there's an escape path for the gas through the firing pin hole.

In a casehead separation, the casehead will usually still seal the chamber, so there's nowhere for the gas to go. A little gas will reach the chamber, but there's not enough flow to cause any damage, IMO. But I suppose it depends exactly where the case separates and the construction of the case. There will be some exceptions.

If cracked necks and casehead separations resulted in defacto flame cutting of the chamber, the HK G3 fluted chamber would need to be replaced every 1000 rounds.

 

[Dave P]

8 or 9 reloads isnt enough for you?? Don't be so cheap with the brass - I don't think your rifle was cheap.

Even if the brass cost $1 each, 8 reloads equates to only 12 cents per shot.

 

[FROGO207]

I would try some lesser brass and see what it's case life/accuracy was as well. Might find something that is better or the same performance with more reloads per piece of brass. Just sayin.

 

[savanahsdad]

, depending on the action used. A Rem 700 type is safest. A Savage may blow the extractor out of the bolt.

umm .. Wrong ! all 6 of my Bolt Actions are Savage's, over the years I have had more than a few heads crack about half way around from using old brass/range brass for testing/fowling shots , the worst thing I ever did was switch out a Seirra with a Nosler not knowing the Ogive was not the same , (first year of handloading 1997) loaded them with the same powder, brass, primer, and COL, had to use a rubber mallet to open the bolt , the primer blew out and jammed the ejector pin in the bolt , extractor was fine, Never had a issue with any Savage extractors nor have I ever seen anyone else have a Savage extractor issue

 

[coloradokevin]

8 or 9 reloads isnt enough for you?? Don't be so cheap with the brass - I don't think your rifle was cheap.

Even if the brass cost $1 each, 8 reloads equates to only 12 cents per shot.

8 or 9 would be fine. As I said, this was number 5.

I would try some lesser brass and see what it's case life/accuracy was as well. Might find something that is better or the same performance with more reloads per piece of brass. Just sayin.

Believe me, I would if I could. It seems like "lesser" brass brands have been made out of unobtainium ever since the panic buying started a couple of years ago. Lapua brass and a couple of other similarly expensive brands are currently available, but there's really no Remington brass (or other cheaper brands) currently in stock in .260 Rem (at least that I've found). I've been happy with Remington brass in my other precision rifles, but I just haven't seen it in this caliber. One of the reasons I like to use cheaper brass is that it's less of a loss when pieces are lost during competitions, or other shooting in field conditions.

 

[Walkalong]

This rifle also has a fairly tight chamber, so I can't see this being a excessive headspace issue with the rifle.

While that seems logical, it isn't necessarily true. Besides, tight which way. Side to side, or breech face to shoulder?

You can over size brass and cause separation by moving the shoulder too far. The only way to know if you are doing that is to measure shoulder position from new cases, fired cases, and sized cases.

As posted, the brass doesn't fill the chamber completely after one firing due to it rebounding back, which is one trait that makes brass desirable for cases. Measure it again after each firing. Or take one case, hammer it with full power loads for three or four firings and see where the shoulder is then. That is going to be pretty close.

If you are getting the rut/bright line after five firings on Lapua brass, there is too much case stretch going on.

Part of what I posted in the thread I linked to:

Case head separation happens when we fire a case over and over and when it has room in the chamber to stretch. If a rifle has excessive mechanical head space a case can do this on one firing. Another way is if we push the shoulder back way to far and create "artificial" headspace, or excess clearance in the chamber. It adds up to the same thing. The case has too far to stretch and it thins near the case head.

When we fire a bottle necked rifle round the firing pin pushes the round forward until the shoulder stops the round in the chamber. Then the pressure blows out the case to fill the chamber. The softer front of the case grips the chamber walls sealing off the hot high pressure gases from blowing out of the rear of the chamber. The harder thicker case head holds pressure in the rear. This is most important job of the brass, to contain the gases/pressure and hold together during firing. The brass case, with help from the chamber walls and breech face, seals the open rear of the chamber, and forces all the gas forward down the barrel.

When fired, the softer front of the case is gripping the chamber walls, while the harder rear of the case which expands minimally is free the move rearward to the breech. This cause stretching of the case, normally right where the thicker web transitions into the thinner wall. It stretches because the front of the case holds tight to the chamber wall while the rear does not. It slides to the rear until the breech face stops it.

This is why we do not want to over size, or push the shoulder back too far, on our cases, as it will increase how much the case stretches each time and lead to failure sooner than necessary. We can use a case gauge like those from Wilson, or various tools to measure how much we move the shoulder. Ideally we want to move the shoulder .003 or less.

 

[243winxb]

Savage vs Remington action

umm .. Wrong !

Not a separation but a pressure release ....... http://thefiringline.com/forums/showthread.php?t=465482

The (savage) rifle didn't suffer much damage other than to the extractor, which was blown to the outside of the bolt.

With photos at link.

 

[Curator]

I have a .260 Remington bolt rifle and Lapua brass. I have reloaded one batch 15 times without and signs of failure. I "fire-form" the cases on their first loading with the bullet seated way out. When the round is chambered, the bullet contacts the rifling leade and holds the case head against the bolt face. That way, the only case stretching is the neck and shoulder. Thereafter I use the Lee "Collet" die to reload. Case life is greatly improved. I have used this technique on my Lee Enfields (notorious for case-nead separations) with equally satisfactory results.

 

[savanahsdad]

Not a separation but a pressure release ....... http://thefiringline.com/forums/showthread.php?t=465482 With photos at link.

well,, now I can say I have read about one, but still haven't seen one, and that gun was not damaged ,he just had to push the extractor back over the detent ball, after reading both pages of that form ,it is clear that was a freak accident , after two pages no one is sure what or why that happened ,I did see an extractor failure with a blown primer on a Winchester mod70 but that will just get us more off track.


OP: as to not being able to find other brass. I can't find any 25-06 , so I have just been buying factory ammo, and shooting it , this gives me once fired brass with out having to shoot up my reload components , costs a bit more, but there all loaded up and ready to go , about $135 for 100 rounds (5 boxes) -VS- 28 cents a bullet, 3.5 cents a primer , $30 per 100 brass and a few bucks in powder , so about $65 to make your own , going this rout may cost 2X but if the brass gets you 3-4 more loads and the fact you get the brand brass you want it may all be worth it in the long run ,

 

[blue32]

I'm up to 8 reloads on various lots of Federal .260 brass with no signs of wear. Most of my loads are using 140's at 2600 - 2700 fps out of a Savage 11. Dies are RCBS.

 

[coloradokevin]

A BIT OF AN UPDATE:


I took some brass measurements tonight (detailed below). The short version is that it looks like I have an average difference of 0.0086 inches between the 5x fired cases that showed signs of incipient separation and some cases from the same lot of brass that were fired 4 times and had just been full length resized.


The measurements (randomly sampled from three lots of fifty pieces) were as follows:

GROUP 1 (the pieces with incipient case head separation — Each had been fired 5 times):

1) 1.570"
2) 1.569"
3) 1.569"
4) 1.570"
5) 1.570"

AVG: 1.5696"

GROUP 2 (4x fired brass from the same lot that had already been full-length sized):

1) 1.561"
2) 1.562"
3) 1.560"
4) 1.561"
5) 1.561"

AVG: 1.561"

GROUP 3 (Virgin Lapua Brass - Same Lot - Never sized by me):

1) 1.561"
2) 1.561"
3) 1.561"
4) 1.563"
5) 1.563"

AVG: 1.5618"

 

[243winxb]

The difference of 0.0086 inches doesnt seem to be a lot, till you add in spring back of the fired brass. A die adjustment is in order for less shoulder bump.