case head seperation?

[Pons]

BMAN73,

Agree with Johnboy on the paperclip check

Originally Posted by Johnboy

... take a papper clip and pull one end out then put a little 90* on the end.then you run it into the case to feel for a ring starting to form around the inside of the case.you can even form a point at the tip before you put the 90* in the end this will help out to feel the ring...
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Saw a nice article by German Salazar on this with a good cut case picture.

Causes of Case-Head Separation within AccurateShooter.com

-Pons

[kc0pph]

I shoot a 270 in a Rem 700. I load Remington or Winchester brass (depending on lot), I actually got head seperation because i was not watching closely. Ill try to post some pictures up when i get off work.

With new brass i get the same look you get after FL sizing, i wash it in a solution of Salt, Vinegar, and Laundry Detergent (PM me if you want to use this as there are some very special conciderations), then dry and tumble in green lyman media.

Now i am one of those people who gets the most out of everything. I had well over 25 loadings on the brass when i got the brass from my father. He had several loadings on it as well, and it was bought back in 87.

I still F/L size as i have not gotten a Neck Sizer yet. My load i was using when this happened, was the same load for ALL of the previous loadings. 56.0 gn H4831 LC (the old stuff still going through surplus).

It blew a ring about 3/4 around the case right on the spot i saw before and i always see. Like a moron I kept on shooting and payed no attention to my fired brass. Thankfully i did not have any sticking.

Best advice as a 270 shooter i can give you is this. The shiny ring is nothing to be alarmed about. Run a paper clip through your brass every time you fire it. When i feel a ring forming i recycle the whole lot. (I use 12 rd lots). I am going on about 27 or 28 firings on my current brass right now and they all are still running strong.

Bow to the Mighty .270

[kyhareraiser]

after a few reloadings you will see a bright ring on the brass but not close to the bottom like in the picture ..maybe a 1/3 of the way up from the primered end of the brass.. i had a seperation in my 308win. T/C and when i got the brass outa' the chamber i saw what happened so i went through my brass and all that had the bright ring about the 1/3 way up i'm talkin' bout (not like the picture,they are ok) i squished the ends together and trashed them so i would'nt reload them again accidently

[kc0pph]

^^ Good advice. I keep a bucket filled with all my retired brass, and bad range pick up. I squish them all with a pair of pliers, as there are 2 of us using the bench and would not one of them to get loaded. After it gets full (once or twice a month), I take it to the recycling shop and pick up 150 or so bucks. Now i pick up several 5 gallon buckets of brass every few weeks, and always pick up the rimfire stuff as well. Makes good recycling.

[MagnumManiac]

Originally Posted by bman73

Was shooting the .270 a week ago while letting the other gun cool and for the first time I looked at the brass coming out of it(has always just used factory ammo on it, only gets shot a few times a year usually) and noticed the rings on the bases first. After looking closer at them I could actually feel a bit of a ridge with my thumb on them. Is this case head seperation happening here? I have never actually seen it before and would like some input before I get all stressed out and spend a bunch of money that I don't need to. They were Federal Power-Shok 130 grn. soft point. I was shooting them out of a Parker Hale Safari .270 win. If this does appear to be case seperation would the likely cause be excessive head space? I apologize for the poor pic quality but it didn't transfer well from the phone to computer for some reason. I will try to put some better ones up later but for now I will post these and see what anyone thinks. Thanks in advance

All the answers given so far are spot on, but no one has said what you're looking at!
That is the normal expansion line, where the solid web meets the case wall. The reason the rear of the case looks shiny is because it doesn't expand to touch the chamber, whereas just in front of the web the case expands to touch the chamber leaving behind the tooling marks and dulling the brass.

As kyhareaiser pointed out, most case head separations occur about 1/3 up the case, a bright shiny and wide ring appears before the actual separation, normally in excess of .050" wide, it looks very different to the normal thin expansion line.

[kc0pph]

Attached are 3 pictures i took of a 270 Winchester Case with over 30 reloads through it. I retired the whole lot after i had a few Separations. From reading here a lot would say that my cases are safe. NONE of them are. I cut away several of them and the line is clear as day. The Line is about 1/10th of an inch, and is on the outside as well. Be careful and check your cases. If your unsure pick the worst one and cut it open using a hacksaw. I just did it for the first time.

Thank god the Separations i had were all partial.

[bigedp51]

The case expansion or bulge you see at the base of the case is the difference between the actual diameter of the chamber and the diameter of the cartridge case. The chamber diameter of the .270 is to be .474 and the case base diameter is allowed to be .473 to .463 by SAAMI manufacturing tolerances.

Bottom line, the larger the diameter of the chamber and the smaller the diameter of the cartridge case the more pronounced this bulge will be.

The headspace of each rifle and how far you full length resize the cartridge case and how the case is constructed in the web area determines case head separations.

Below is an example of .303 British cases both fired in the same rifle, the case on the right has a smaller base diameter and expanded outward further than the case on the left.



When full length resizing you only want to push the shoulder of the case back .001 to .002 to allow minimum chambering clearance. If you push the shoulder of the case back too far each time you resize the case it will stretch in the base web area to meet the bolt face each time the case is fired and case head separations will occur.

If you reload proper fireforming and reloading techniques will help prevent case head separations. I use a RCBS Case Mastering Gage to check my cases for stretching and thinning in the web area.



Below are helpful tools to use when resizing cases and only push the shoulder of the case back .001 to .002