Lapua Brass Problems

[fieldratsniper]

You sure thats not a fold from say a kernel of powder in your chamber or die which dents the sholder then after firing irons out? I had this happen once when I pulled a live round from the chamber and dumped powder in the action. It was ball powder and the next couple cases upon extraction had a dent I loaded them a second time and they looked like that after firing, I threw them away just to be safe. I bought 1000 rds of 6mbr brass from bruno about three years ago and they have been golden, no split necks nothing. I kept 600 for myself and parted out the rest to some friends no failures from my brass none that I have heard of from my buddies.



Lance

yeah, its hard to see from the pics, but those look like "imprints" of some kind (i was expecting to see a "split"). are you sure they go all the way through? maybe you could put a "chamber/bore" light inside the case in the dark and see if there is light coming through....

i had a little piece of something in my 223 chamber and it would put a little dimple in the brass until i got it cleaned out really well.

and i noticed that your brass was reloaded. did you only notice the marks after you reloaded them, or have you found the brass like that right after firing?

like lance said, maybe you have something in your dies that is doing that to them. they look full length sized. so maybe the FL die has a foreign object in it.....

sorry if there was something in an earlier post that i missed.

Jeremy

 

[fieldratsniper]

I just did another box of brass and again I lost 3 pieces.All I did was to expand to 6.5mm and I had one case split almost all the way to the body/shoulder junction.
Lynn

pics???

 

[jo191145]

Those are for sure the strangest splits I've ever seen.
They don't look like the usual foriegn object in the chamber/die marks or splits.
Looks like bad metallurgy to me. Definately send them back to Lapua. They need to know.

I've had Lapua harden to the point of non obturation. Not a single split. Annealed it and its still all running perfectly.
Just recently necked up 100pcs of older Lapua 6BR to 30BR. One step 6 to 30. Lost one piece. I find that quite acceptable. What you guys are seeing is not normal.

 

[LRPV]

The splits I am getting are the longitudinal normal old kind of splits. Heading out west to kill some prairie dogs this morning. Wish me luck.

 

[jo191145]

lrpv

Went back and reread your posts specifically. Trust me, what your seeing is not normal, not even close.
Properly cared for 100pcs of good brass could last the lifetime of a barrel without losing one case to splits.

By all means go splat some rats. I would'nt pass up a chance to go P-doggin.
All these split necks while shooting aren't doing your chamber any favors though.
If blown primers can etch bolt faces I would imagine the hot gases from splits could act as tiny cutting torches also. Maybe
Good Luck and have fun.

 

[spclark]

I went back & did some CSI-style enhancement in Photoshop on two of your images, came up with some ideas. They're not retouched in any way; I lightened & compressed the tonal range to make subtle details more apparent.

In the attached PDF, note the presence of what looks to me to be metal inside the crack near circle 1.

The lighting in all three images seems to suggest the surface deformation is not sharp-edged as a crack probably would be, but more rounded.

Just above circle 2 one of the deformations changes direction just to the right of the circle, almost as though some kind of contamination were present (grains of powder?) between the case shoulder and chamber when that round was touched off. The surface just above circle 2 appears to be depressed somewhat, most strongly at the intersection of all the lines.

Below circle 3 that straight line pattern extends beyond the two angled lines to the left and right, perhaps indicating two, maybe three pieces of contamination all overlapping at the X between the two circles when the round was fired.

All the grooves appear to have slightly rounded ends.

(Here's my original post

Those pics... I've never seen "splits" like that.

Usually you'll see some blackening along the edges when a case splits lengthwise along the body, not often when necks split but they're under more pressure.

Head separations are in an entirely different category altogether.

The cross and dog-leg are particularly odd; they look to be embossed, like something was between the case shoulders and the chamber when those rounds were touched off. Some kind of contamination. I'm no metallurgist but the failures I've seen usually follow a more-or-less straight line.

Be interesting to know what you eventually learn about this. Please continue to investigate & then post your findings to the forum.

Here's a link to Lapua's own Feedback web page:

http://www.lapua.com/index.php?id=839#314

 

[kitsap]

Shooter Bob,

Looking at your pictures I am of the opinion you had some debris in the chamber when you fired the rounds. My guess would be a bristle from a cleaning brush or a thread from a cleaning patch. When the case is removed from the chamber after firing did you see any soot or sign of powder fouling around the areas you believe are cracks?

DougF

 

[ShooterBob]

Thanks for all the input. At this point I'm sure that what I'm seeing are imprints. They are very shallow and I can see the bottom of all of them. I shot 50 of them today which is the 4th firing. There were no splits of any kind. There were also no new imprints and the ones that were already there seemed to iron out a bit. As far as how they got there, a bristle from a bronze brush makes the most sense. I honestly don't know when it happened but I'm almost certain it was not in the unfired cases.

 

[RonAKA]

I recently weighed 100 cases from 6BR lot number P00426203 (cardboard box, unopened). Average weight was 125.89, and Standard Deviation 0.55. Have not loaded them yet, so no good way to predict neck thickness, but I suspect they are in the 0.013 range.

However, that said, I don't think the OP's issue is neck thickness. I have some knowledge of metallurgy and strength of materials. If you are getting longitudinal cracks in the neck after two loadings in a tight custom chamber, then there is something significantly wrong with the metallurgy of the brass. One possibility is that they did not anneal sufficiently during the case forming. However, Lapua does not polish out their cases and it should be possible to tell if they annealed or not by appearance. The other possibility is that they grossly over annealed and took all the zinc out of the brass. If brass is left to sit for long times in a wet environment with bacteria, the bacteria can actually eat the zinc too, but that seems extremely unlikely.

The most probable cause would seem to be gross over annealing, or the brass was bad from the start (grossly out of spec).

In any case I think you have a legitimate concern about the quality of the brass you got, and I would hope Lapua will respond.

 

[fieldratsniper]

yep, like i said before. once i got my chamber good and clean. the dimple that the foreign object was leaving were blown out after being fired in the clean chamber.....