Case head seperation?

I had to trash several pieces of brass today due to bulges in the brass near the case head. I had shot and reloaded the brass several times and never noticed any pressure signs on the primer or case head before. I checked all the specs on the brass and all are good just starting to see a bulge about a half inch from the case head.

I have shot max loads and slightly over before but took care looking for over pressure signs at the time. I am not sure because I am not shooting on or close to the max charge for the round.

Reckon the case life has been reached or I am not shooting the correct propellant? Shooting a .243 and using 40.5 grains of IMR4350. Not seating to the lands. Seated .025" off.

Looking for some kind of feedback ideas of potential causes.

Thanks

Powder, charge, and COL seems right. I'd say double check headspace. If that's good then case life might be at an end.

FWIW, I've shot slightly over max in my AR 6.5 Grendel for a long time (12+ reloads per case) before I saw what you're seeing. The case had the same separation you're describing. This was with Hornady brass.

What brass are you using and how many reloads before separation?

I have been checking the headspace. According to SAAMI specs they check out good. All of these are Winchester brass and they have been shot eight times. I only full length size as they become harder to chamber. I usually just neck size until the rounds become hard to close then I full length size again.

Thanks for your reply. I know very few folks that reload rifle ammo and it's really nice to have this knowledge base to ask for help.

If it's a factory chamber it could be a hair oversized working the brass too much. I think if you get 8 loads out of a Winchester case you're doing good. Save up and buy yourself some Lapua.

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Originally Posted by 243LPR

If it's a factory chamber it could be a hair oversized working the brass too much. I think if you get 8 loads out of a Winchester case you're doing good. Save up and buy yourself some Lapua.

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It is a factory chamber. I have never measured it so it sure could be. It's a savage 110, I don't know if that is typical or not for them to run oversized or real close?

I just ordered 100 pieces of Lapua the other day. They should be here tomorrow.

Thank you

It doesn't sound to me like you are describing case separation, but normal case expansion just above the case web, the thicker portion of the case. You can check this by sectioning a couple of cases lengthwise and look at the wall of the case. Look for a drastic thinning just above the web.

Since you are not FL sizing your brass every time, but only as necessary to get it to chamber, you are not working your brass very much. Your load is not particularly hot, and case life should be very good. I have several hundred cases of mixed mfg that have gone through this model 11, some reputed to be very soft, and the only issue I've found is loose primer pockets in some.

I'm loading a little hotter load in my 243 and yes, the brass shows some expansion like yours, but everything is safely within limits. Brass is not growing, and unless it's growing, there's no way the brass is thinning out and close to separation as there's no evidence the brass is "flowing".

I run Lapua in my 22-250 and also just neck size as much as possible, but also set my FL die to bump the shoulder back .001 when necessary to chamber. I'm getting 4 to 5 loads before FL sizing.

You should get very good life out of your brass when working it as little as possible. Primer pocket looseness, not case separation will probably be the reason you will have to toss any. Annealing your brass is a good way to extend case life too.

Usually you can tell if the chamber is slightly oversized. During full length sizing brass fired from oversized chambers will take more effort to size. You can also take a bunch of range brass, measure towards the case head, then measure your brass. This should give you an idea how loose or tight your chamber is.

For example, the brass (using Federal for now) fired from my LR308 without any sizing will chamber into my Axis without issue. Brass fired in my Axis will not chamber in my LR308. Axis has a loose chamber and LR308 had a tighter chamber.

Some brass just doesn't hold up very well, but I am surprised your Winchester brass is giving out. I'm using Winchester brass for my 284 Win and I have around 10 loadings with no issues yet. On a side note, I had a few hundred 308 brass, headstamped SBS, that were exhibiting loose primer pockets only after the 3rd firing, hence now using Federals. You will be happy with the Lapua brass. Let us know how they work out for you.

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Originally Posted by 243LPR

If it's a factory chamber it could be a hair oversized working the brass too much.

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:cool::becky::first: in combination with the reloader over resizing the brass. Are you getting carbon on the case body?

http://www.milsurps.com/images/impor.../308fail-1.jpg

http://www.milsurps.com/images/impor...308fail2-1.jpg

No just a little on the neck.

That's exactly the same point as the shinny bulged line on my brass but no separation in mine yet. I tossed them before they reached that point.

Below are two British .303 cases fired in the same Enfield rifle. The case on the left is larger in diameter and has .010 thicker case walls in the base. The case on the right is smaller in diameter and expanded more to contact the chamber walls. Neither case stretched or thinned in the base web area when fired, and shows that a smaller diameter cases looks worse when fired but the expansion ring means little.

http://i122.photobucket.com/albums/o...psshjfudwg.jpg

Below on the far left a new unfired Remington .303 British case. In the center a once fired case and on the right a case fired and full length resized four times. This case expanded but cracked and started to separate and my point being radial base expansion does not mean the case is about to separate. The actual stretching and thinning happened above the radial base expansion.

http://www.milsurps.com/images/impor...houldera-1.jpg

Below same case at a different angle.

http://www.milsurps.com/images/impor...IMGP5191-1.jpg

Below my RCBS case mastering gauge set up to check for thinning in the base web area. (a $100.00 fancy bent paper clip)

http://www.milsurps.com/images/impor...IMGP5203-1.jpg

Nice job Ed.

303 Brit is notorious for stretching cases. I've had to dig more than one case out of a chamber after the head broke off.

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Originally Posted by bigedp51

http://www.milsurps.com/images/impor.../308fail-1.jpg

http://www.milsurps.com/images/impor...308fail2-1.jpg

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Wow, very surprised the Remington brass beat out the Lapua! Did not expect Norma to be so good either.

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Originally Posted by bigedp51

http://www.milsurps.com/images/impor.../308fail-1.jpg

http://www.milsurps.com/images/impor...308fail2-1.jpg

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Is there an article for this study? Link anyone?

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Originally Posted by s3silver

Is there an article for this study? Link anyone?

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I think it came from Handloader magazine, the ammunition was fired in a new Savage .308 rifle. It didn't state what the actual rifles headspace was or if the press was setup for minimum shoulder bump.

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Originally Posted by 243LPR

303 Brit is notorious for stretching cases. I've had to dig more than one case out of a chamber after the head broke off.

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With a rim thickness of .058 and at maximum military headspace of .074 you will have .016 head clearance or airspace between the rear of the case and the bolt face.

http://www.milsurps.com/images/impor...stretch1-1.gif

A trick I learned from the Canadians is to slip a small thin rubber o-ring around the case to hold the case against the bolt face to fire form the cases.

http://www.milsurps.com/images/impor...ame_0001-1.jpg

After fire forming you neck size only and let the case headspace on it shoulder.

http://www.milsurps.com/images/impor...eadspace-1.jpg

The problem is the military chamber is larger in diameter and longer to the chambers shoulder than commercial SAAMI standards. Meaning the full length resizing dies are much smaller than the chamber and overwork the brass.

Quote:

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Originally Posted by bigedp51

It didn't state what the actual rifles headspace was or if the press was setup for minimum shoulder bump.

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exactly so how can anyone come to a realistic conclusion about FL sizing with no actual info about the test other than brand A failed xx brand B failed xx.
now im not arguing FL sizing VS neck sizing because its a waste of time...i say do what works for the person doing the loading...but i am hear to say that i have had 28 loads on 260 lapua brass that still had decent primer pockets when i tossed them...ive also tossed brand new 260 lapua in the trash after the first firing...the difference was 400FPS with the same bullet....ive also had 17 loads on nosler brass in a 300wm with 210g smks at 2900+ fps....with 13-15 loads been the norm.

now i agree if your bumping the shoulder back .005+ every time you FL size then you are definitely over working the brass and contributing to short case life BUT pressure is the biggest killer of brass not FL sizing...if the FL sizing die is set up correctly...again im not arguing which way is better just pointing a few things out because i FL size every time and have been for about 7yrs now.

After reading all the replies and thinking about it I decided to do a little measuring to see if I could find anything abnormal. I pulled the firing pin from the bolt of 2 rifles so that there could be no tension on the case as it was chambered. I took a bunch of fired brass and picked through them until I found a case that would not allow the bolt to close or drop easily as it was closed. Measured all of the cartridge dimensions and wrote the measurements down. I looked though all of the material that I could find and in both cases the headspace spec was considerably different that what I measured with a comparator. The .223 would not chamber a fired case with a headspace of 1.461 but the spec says 1.467. The .243 that I measured which was the reason for this post initially measured out that 1.625" would not chamber. I set both full size dies up and started adjusting them a little at a time until I was able to bump the shoulder back enough for the bolts to drop with ease. I measured the change in head space after every cycle of the die and settled on a shoulder bump of .003" for both rifles.

I would not think there would be that much difference between the published SAAMI spec and these rifles chambers unless it is just the difference in my gages and/or methods of measurement.

Thoughts?

Pending case head separation is evident by a bright ring around the case head, at the point where it will separate, as shown in the photos above. Watch for that, not bulging. Winchester cases and Remington, are just fine. Buy a broken case extractor, and keep it in your gear. You may get a complete separation some time and need to remove the portion in the chamber. No need to spend the extra money on Lapua or Norma. They're good; maybe they're better, but not that much better.

bigedp51 that is excessive headspace.

Thanks, I keep my eyes peeled. I'd like to keep my digits and eyeballs for a little bit longer.

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Originally Posted by Arky 223

bigedp51 that is excessive headspace.

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I collected Enfield rifles and any books and manuals I could get my hands on for a very long time.

The military Enfield chamber was reamed larger in diameter and longer to the chambers shoulder in 1914. This was for two reasons, there was a political ammunition scandal over "who" was awarded contracts to make ammunition for the military. Some of this ammunition was so poorly made it was hard to chamber and the mud of trench warfare complicated the problem further.

If you can learn to reload the .303 British case and get 32 reloads with moderate pressures you will understand the word "headspace" and old surplus rifles.

My No.4 Enfield rifle below has had the headspace set below minimum just kissing the rear of the case to .010 over max headspace. Normal headspace was min .064 and max .074 and the Australians set .084 as emergence wartime headspace. And this rifle had the headspace set from .057 to .084 and I'm still here alive and well with all my body parts. Bottom line, chamber pressure, and the strength of the case have the biggest effect on your cases life. And the reloading manuals data for the .303 British and other older rifles are for the weakest link in the chain, meaning older rifles made from softer steels and weaker actions.

http://www.milsurps.com/images/impor...MGP13551-1.jpg

If you look at a SAAMI cartridge and chamber drawing headspace is listed as min and max with .010 in between the two. And many older milsurp rifles have headspace over maximum and measuring the base of the case above the extractor groove will let you know when you are pushing the case limits.

The link below does not tell you chamber pressure, it simply tells you the strength of the case and how much pressure it can take before you reach its elastic limits.

Simple Trick for Monitoring Pressure of Your Rifle Reloads
http://www.hodgdonreloading.com/relo...-rifle-reloads

So ask yourself "why" a new Remington 700 in 30-06 can't be loaded to .270 Win chamber pressures, its just a necked down 30-06 case. And ask yourself "why" the table below was even made up.

http://i.imgur.com/EPcuYSG.jpg

Below are fire formed .303 British cases using the rubber o-ring method. The rubber o-ring serves two purposes, it holds the case against the bolt face so the case will not stretch and thin. And when the o-ring is compressed it centers the small diameter case in the rear of the "fat" chamber. If this wasn't done the case would just lay in the bottom of the chamber and after firing if the case was stood on its base it would look like the Leaning Tower of Pisa.

http://i.imgur.com/FCHGvIZ.jpg

These cases are fire formed with reduced loads and using .312 100 grain pistol bullets.

http://i.imgur.com/HHDfGl9.jpg

And when forming 100 to 200 cases the reduced loads help make the brass butt plate "softer" and they are fun for 50 yard plinking.

http://i.imgur.com/HyLFfuv.jpg

Case forming load at lower left.

http://i.imgur.com/tyJBZe1.jpg

Bottom line, your cases will not separate if properly fire formed and resized with minimum shoulder bump. Meaning staying within the brass elastic limits and being able to spring back without stretching.

You can fire form your cases by seating the bullet long and jamming it into the rifling to hold the case against the bolt face. You can also create a false shoulder and let it hold the case against the bolt face.

Or you can fire form using the COW method (Cream of Wheat) but the firearms industry does not stand behind this method. (nor should anyone)

http://i.imgur.com/eHM6WZi.jpg

The bulge can also be that the sizing die did not size that part of the case. I see this with 243w 260r 7-08r 308w and many others.

Your chamber is generous around the head and the sizing die doesn't reach all the way down the case, hence why there is a lil bulge, but it's not dangerous.

Like others said, cut a piece of brass down the middle with a dremel and check for brass thinning above the head.

If I missed any of this my apologies. Just a few questions.

Is this an aftermarket barrel? Does it have a large chamfer leading into the chamber on the barrel breach? Do you have a picture of the fired brass with bulges? Is the chamber gauge standoff more than say .150"? Have you taken a dial caliper and compared the mouth of the chamber dimension with a SAAMI chamber drawing?


Look around page 83

http://saami.org/specifications_and_...FR.pdf#page=13

Should be in the ballpark of .471 plus or minus....

I shot about 50 rounds through my .243 today with new Winchester brass. I measured the headspace before and after and saw not growth in the headspace. I was below the load max stated by Sierra but still see the little ring starting to appear just above the case head.

I shot the best group I have ever shot with this rifle today. It was a four shot group that measured 0.450" with new brass. 85 grain SBT over 37.2 grains of IMR4320. Then a second best group of 0.600" with a 100 SBT over 40.5 grains of IMR4350. Best groups to date with this little bone stock savage.

Congratulations, gunrack! That's good progress and definitely "minute of deer" accuracy, and the reason we love to hand load.

In case your interested, the load I've worked up in my 243 with a 22 inch, 9.25 twist "pencil" barrel is 87 grain V-Max at .012 off the lands, 43.5 grains of IMR-4831, CCI-250, and Winchester brass. Haven't quite got it completely tuned, it's shooting well, just not as well as yours.

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Originally Posted by Texas10

Congratulations, gunrack! That's good progress and definitely "minute of deer" accuracy, and the reason we love to hand load.

In case your interested, the load I've worked up in my 243 with a 22 inch, 9.25 twist "pencil" barrel is 87 grain V-Max at .012 off the lands, 43.5 grains of IMR-4831, CCI-250, and Winchester brass. Haven't quite got it completely tuned, it's shooting well, just not as well as yours.

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I just had a good day. A minute of deer is all I really need but you know how it is. we always want them little bitty groups. I feel more confident knowing that the rifle is more capable than I when I get ready to take a shot. Days at the range for me don't happen like that very often. I may never shoot another one like that but I have put in a lot of work on loads on this little rifle. I will make a note of that load you suggested and give a shot some time. I love to tinker with new loads but it sure gets aggravating sometimes. I haven't got enough hair left to keep pulling on it the way I have been lately. LOL