Brass Rupture After 3 Loadings?

[Danderdude]

Howdy all,

I was shooting my K31 earlier and had a small case rupture. There were no signs of anything bad, except that I like to catch the ejected cases and just happened to notice the problem. Unfortunately my camera won't take a good picture of it so you'll have to bear with my description.

There is a vertical slot 1/32" wide and 1/8" long centered on the junction of the neck and shoulder. It does not extend to the mouth or past the bottom of the shoulder. The hole looks EXACTLY like the left pic, but in the right pic's location. Pics are from the Lee ABC's of Reloading book.


This is pretty new Prvi 7.5 Swiss brass. I purchased 100 cases through Grafs a month ago. Thus far it's only fired:
16.5gr 2400 under a Lee C312-155 (WW, checked) sized to .309 with CCI LRM (250) primers, twice
And at the time of the incident,
32gr H4895 under NOE 311 180 FN "K31" bullet, Hardball, checked, sized .309, CCI LRM (250)

The brass is lubed and FL sized through Redding K31 dies, and tumbled in walnuts before this loading. I even cleaned all the primer pockets.

The cases come with annealed necks, and I keep my factory loaded Prvi separate from my bulk Prvi brass.

I have not been reloading long and this is my first case rupture. Is this natural or have I done something wrong? I was under the impression that brass could take quite a few more reloadings, or at least higher-power reloadings than I've been doing, before I start seeing issues like this. Overpressure is impossible, as 64gr of H4895 overflows and I am very tedious with my loading safety.

So, don't be shy. Think this is a one-off, a mfg problem, an annealing problem, or something else together? Sound off.

[mpmarty]

Hi welcome to the insanity.

That looks like a bit too much lube when you resized the brass and caused a hydraulic dent which failed on firing. Not uncommon. Too much lube on the shoulder area. Check the vent in the resizer die with a small paper clip. Good on you for using the correct die set. RCBS dies are totally wrong dimensions for the K31 and AFIK only Redding makes the correct die to proper specs.

[Blammer]

if it's as you described I'd chalk it off to case failure due to brittle brass.

this is presuming that there was no indent in the case like you have in the picture on the right (with the projectile in it)

[geargnasher]

+1 on hydraulic dent in the shoulder from too much lube on the neck. As for the split in the body, "stuff" happens in an imperfect world. Cull it and don't worry about it unless you get a bunch more. If you get a bunch more, check before and after dimensions in the failure area to make sure the brass isn't being overworked by an oversized chamber.

Gear

[madsenshooter]

Not to worry, the flaw you have described is not one to cause a blowup, unless it happened to be back on the head of the case. Anything mass produced is going to have an occasional bad one get by. Some of you guys are missing something, pic one is what the flaw is like, pic two is the location, he didn't have a dent like that, least not that he noticed.

[John Boy]

+2 on hydraulic dent in the shoulder from too much lube on the neck. Indication of the same above the web of the case

Best lube I've found is Bag Balm for FL and resizing. Just wipe the cases with your index finger & thumb

[geargnasher]

I'm seeing a lube dent on the shoulder, there might be a split to the left of the dent, mostly on the neck and extending partway onto the shoulder, but it could just as easily be a scratch.

Gear

[Danderdude]

I love you guys. I've probably spent 100 hours reading on here before even ordering a reloader and I still learn something new every day. I'm proud to say that my first reload was a handmade cast reload.

mpmarty, if there's a vent hole on there, I'm not seeing it. I did lube the threads on the decapping rod, though. Should I wipe it off to let air move freely through the threads?

madsenshooter, correct, there were no dents. Though I have seen a couple of dents in the necks, they were from a small amount of greasy walnut dust stuck to the case. I cleaned them and shot the dent out without a problem. Very slight dents can cause this?

Blammer, how many firings should one expect before the case necks get hard and need to be annealed? I understood it was 10+.

[Danderdude]

John Boy, I'm currently using Hornady Unique case lube on a used RCBS lube pad. Got them for a buck a piece from the gun show.

[geargnasher]

There should be a vent hole in the bottom of one of the threads that coincides with the neck/shoulder junction. It will be about a .015-.020" hole. They get plugged with stuff like walnut dust. Roll your cases on a towel before putting them on the lube pad to remove tumbler dust, and go easy on the lube. Most lube dents shoot out ok, but the brass might crack in that location in the future.

Gear

[popper]

The vent hole may be under the locknut. I've had similar failures with purchased 'once-fired' brass for 30/30. Inspected the cases pretty good. Not a split, a burn-out slot. Light loads too. I just buy new brass now.

[Boerrancher]

There are lots of causes for case failure, if it starts happening on a regular basis in the same spot then there may be a problem. I shoot a lot of old brass at the range and keep my newer brass for hunting, so it is nothing for me to have a case go bad on me every trip to the range. Brass that has been used a lot or brass that has sat loaded for many years will have case failure sooner than newer brass. Also every once in awhile a bad piece of brass gets through, and after a couple of shots gives up. As mentioned several times, if it keeps happening in the same spot regularly then start to look for trouble.

Best wishes,

Joe

[stubshaft]

I bought a bag of new Pvri brass for my Hornet and had about 60% failure rate from splits. Threw the whole lot away and swore I wouldn't buy them again.

[Maven]

Danderdude, I too have experienced burn through's in that location with several brands (and calibers) of brass. It could be from a lube dent or it could simply be poor quality control by Privi Partizan. E.g, I was sorting some unfired Privi 7.62 x 54R brass yesterday and discovered a split in the body identical to the one in Lee Precision's photo. Again, this was NEW brass. A few things you can do: Keep an eye out for splits (neck) on the rest of that brass. If you find more than 1:50, consider annealing it. If you still find them after annealing, throw them into your recycling bin or maybe return them to the distributor (Grafs?). Lastly, reset your FL sizing die so that 1/16" of the neck is unsized. That way you won't push the shoulder back, the case neck will self center in the chamber, and you won't overwork the brass. Your K-31 will chamber them just fine, btw.

P. S I didn't see stubshaft's post, #14, until after I posted the above. His experience with Privi also points to poor quality control.

[madsenshooter]

It's interesting to see such comments about PRVI. That's what the young lady who recently had the Garand KABOOM in her hands was shooting, and not reloads. Perhaps a bit of quality control problem at PRVI since the explosion at the factory?

[Danderdude]

On the topic of vent holes, from the Redding Tech Support website:

A popular misconception is that sizing dies need a "vent hole" to release air or excessive lubricant. It can be easily demonstrated that a vented die will also dent cases if excessive lubricant is applied to the cases, case dimensions are not compatible with the sizing die or the case shoulder is being bumped excessively.

http://www.redding-reloading.com/tech-line-a-tips

Just thought yall'd like to see that.

[geargnasher]

Ad hype to justify saving a buck on drilling vents.

If you have too much lube it will dent the shoulder regardless of whether there's a vent or not, quite true, but if you run them into an unvented die too fast it will wad up the case like paper on a soda straw. Lube, even with a minimum applied, will accumulate in a sizing die, so if it doesn't have a vent you might find you need to be wiping it out every few rounds or use a dry lube.

Gear

[Blammer]

yes 10 + is a good average, some die sooner some never die.

[fredj338]

Cheap brass. So I'll add Privi to the brass I won't reload in high pressure rounds. Right up there w/ Federal.

[Bill*]

forget lube dents. Please read 1st post again...OP says those are pics from Lee manual to show location only. He had a case rupture as he explains in his post