Catastrophic case separation

[Dick Dastardly]

I had a Catastrophic case separation at a long distance side match at Mississippi Fandango last season.  The parted brass nose went with the bullet and swagged into the rifling about 3/4" while the bullet went on to the target.  I had to use a pulled bullet to drive down the bore from the  muzzle to extract the front half of the case.  The photo shows the bullet used to do this as well as the broken case.

I remain puzzled as to why a fairly straight wall case, like the 45-70 would separate.

The load was a compressed charge of 67 grains of Swiss 1.5 Fg over a Fed 210 primer, a 1/8" over powder card wad and a lube/sized Big Lube DD-45-70 500 grain semi spitzer bullet.

Never before, or since has this happened.  I still shoot this same ammo loaded to this same data and have had no problems.

DD-MDA

[PJ Hardtack]

Wow! Your brass looks good, so it might have been just a flaw in one case. Any damage to the bore? What kind of rifle?

[Sloan Dodgy]

I've had this happen to me, though mostly in .410 shotgun reloading.  Once the case had been fired a couple of time the inside became roughened (and in the 'case' of plastic hulls, probably slightly charred), and with a poor case-to-wad fit it would take the forward two thirds of the hull with it.  I've also seen the neck pull off a several-times-fired 450/400 2-3/8" BP Express, loaded with BP of course, using soft lead paper patched bullets.

My guess has been that eventually the inside of the neck got roughened up with firing to the point that a bullet being bumped up hard with a case full of black grabbed the neck more firmly than the case would stand, separating the case.  Like I say, just my guess in my situation.

[PJ Hardtack]

First I deprime my cases at the range, dropping them into a jug of water/vinegar solution. At home, I use a bore mop when washing out the cases with hot, soapy water and after tumbling, I run them through my 5 station RCBS case prep machine.

One of those steps is a pass over the brass bore brush to really clean the crud out. First time I did it with cases that already had the bore mop treatment, I was amazed at the amount of dirt removed.

[hellgate]

Check the  insides of your other cases to see if they are developing a thinned area too. It might be that there is a little bit of headspace and the mouth of the case gets locked against the chamber wall while the rear of the case gets set back a bit. Over time the case stretching creates the separation. It might just be that the crimp carried the separated case a bit further into the riflings where it looks like it really got fire formed in there. what a mess. Glad there was no bulge in the barrel. That would have been more catastrophic.

[Dick Dastardly]

Thanks Guys, and Merry Christmas!

Yes, there were some fractured cases from that batch.  This is the only one that failed.  The rifle is an original Remington Rolling Block (action only) that had been a Spanish 43.  That has nothing to do with it.

I inspected the brass from that outing and found several that were thinned in the same place.  A bent paper clip could feel the thinned area.  Only Winchester brass was involved.  I sort my brass by manufacturer so that explains why only one mfg was involved.

From memory, I'd had a mite of difficulty chambering some rounds that day.  There was a small piece of bullet lead stuck on the extractor.  When I removed that small piece of lead my chambering problems went away.  So, I'm thinkn' it probably was a head space question.

I've got another batch loaded up and will be shooting it first decent weather, probably towards spring.  I'll be watching the brass real close and inspecting the inside of each with a feeler.

Once again, I think that this kind of separation on a straight wall case has to be rather rare.  Thing is, I don't like holding a gun next to my handsome face when it blows up.   

DD-MDA

[Cohagen]

Well Dick you don't have a beard, so at least you won't catch on fire.   Merry Christmas to you and yours

Cohagen

[Drydock]

http://stevespages.com/diagnosingproblems.html

[mehavey]

I had this same problem with a Farmingdale Sharps 45-3¼ back in the early `80s.
I determined that the brass (RCBS) at the time had a rim that was too thin and allowed stretch -- even with BP.
I also found that several cases had by that point also developed incipient separations.



Changed cases to HDS and that resolved the problem (for all intents)

LUBE YOUR CASES TO PREVENT THIS IN THE FUTURE !!!!
(Ignore the trolls who will wring their hands over "bolt thrust")

[Coffinmaker]

DDD,
Actually, case separation in straight wall cases as not all that uncommon.  Whilst I was still a shingle hanging, gunsmith practicing, fixit sort of fella, I saw quite a bit of it.  There are several likely reasons.  Reason number one is excess head space.  Part of the case obturates to
to seal the chamber (the front part) and part of the case doesn't (the thicker rear part) and the case stretches fractionally.  We are talking a little as 10,000 of an inch here.  But it happens several times and that portion of the case becomes thin and brittle.  Upon the final firing, the case separates.  Normally, there is no damage to the rifle/pistol nor the shooter.  It's just a pain to get the pieces out of the gun.
Next common reason is uneven extrusion of the case at manufacture.  There is a weak spot from the get go.  The case stretches a little at the weak spot every time the case is fired.  Then it separates.  Again, normally, no damage to gun nor shooter.  Just the problem of getting the fragments (tech term for pieces) out of the chamber/bore.  
Not to minimize your concern, but it's really no big deal.  Although it is fun in a lever gun when one tries to force the next round to chamber (common) and really sticks the pieces in there.
Continued resizing with carbide dies with no lubricant will also contribute to incipient case separation.
I also suggest ignoring those who purport "bolt thrust" as a contributing factor (horse feathers).
In your particular instance, I'd be betting on a case coming out of the extrusion process with a thin spot.

Coffinmaker

PS:  I only consider case separation to be "catastrophic" when the receiver comes apart with it.  Otherwise, just a bump inna road.

[Professor Marvel]

My Dear Monsieur Dastardly -
you just invented the brass jacketed bullet!
where did it hit, could you tell ?

yhs
prof mvl

[mehavey]

I did mean Lube the case.  Not just for sizing.... but including firing as well.
Don't overdo it.  Just the barest dab of Brylcreem to slick it up and let it
slide back against the bolt instead if sticking up front and stretching to the bolt.

[Ranch 13]

 The 2 biggest causes of separated cases is the inside of the case not being completely clean and the wad hanging up and pulling the case before the bullet lets go, and moisture in the chamber either from excess moisture dripping out of the blow tube, or if wiping between shots not using a dry swab to dry the chamber.

[john boy]

 

The 2 biggest causes of separated cases is the inside of the case not being completely clean and the wad hanging up and pulling the case before the bullet lets go, and moisture in the chamber either from excess moisture dripping out of the blow tube, or if wiping between shots not using a dry swab to dry the chamber.

Thanks Don for the post ... Gent's, this is information not to be found in any of the reference books.  A chamber with moisture does not allow the case to completely seal to the chamber wall - so keep your chambers dry.

A visual example is a case with excess lube on it when full length sized - the case will be wrinkled or have a dent on it with a varying length from the excess lube pressing against the wall of the die
A Blessed and Merry Christmas to All and Your Family

[Ranch 13]

  One thing about leaving moisture in you chamber it is a good way to get a very good impression of your chamber throat. If you can get the half of the case out without tearing it up to much. Easy way to get that broken case out is run your cleaning rod without a jag or brush up thru the broken case to the muzzle, then put the jag with a patch pushed on to it over the shank on the rod, and pull it backwards with a good swift pull..

Merry Christmas to you John , and the rest of you as well.

[Dick Dastardly]

Howdy Ranch, and thanks.

I did the brush and rod trick.  The piece of brass didn't budge.  As shown in the photo, the rifling was engraved into the brass very well.  It was really stuck.  I showed it to Coyote Cap and he said to drive a bullet down from the muzzle to slug the bore and push the brass out.  That worked but it really came out real hard.  That roller has a very strong action, thank God.

FWIW, that bullet didn't hit the gong . . .

DD-MDA

[mehavey]

I hadn't really noticed the rifling imprint `til you mentioned it again.
That sucker really swaged itself into a jacketed bullet for quite a distance.

Holy Mackel `der Kingfish !
Lucky, ...lucky, ......lucky, .........lucky .........  

[Ranch 13]

Howdy Ranch, and thanks.

I did the brush and rod trick.  The piece of brass didn't budge.  As shown in the photo, the rifling was engraved into the brass very well.  It was really stuck.  I showed it to Coyote Cap and he said to drive a bullet down from the muzzle to slug the bore and push the brass out.  That worked but it really came out real hard.  That roller has a very strong action, thank God.

FWIW, that bullet didn't hit the gong . . .

DD-MDA

Notice I said a jag, not a brush

[Dick Dastardly]

In previous case separations, bottleneck high pressure wildcats, I've used a brush on a pistol cleaning rod to push up inside the front piece of brass and pull the piece out.  Not so this one.  But, I've never had a piece of brass separate and go up into the rifling before either.

DD-MDA

[Noz]

I don't see a problem? A change of underwear and a short prayer asking forgiveness for bad language and you're good to go.