Kaboom 💥 Today 😟

[2buffalo]

Well, that's not what I was told, and cups are punched, not drawn, which is what makes the case head.
I am happy to be corrected if that turns out to be the case.

Cheers.

So you don't know what you're talking about. Just repeating what other people told you like you are accusing Pdvdh of doing?

 

[Bob Wright]

Well, that's not what I was told, and cups are punched, not drawn, which is what makes the case head.
I am happy to be corrected if that turns out to be the case.

Cheers.

That part of the process, making "cups" is called "coining".
Step 1 in making a drawn case.

 

[Bob Wright]

Like I posted earlier, and JMHO, but that is not a fracture surface showing at the failure sight. I've done some failure analysis in previous jobs, and no way does metal that fails by being strained beyond its ultimate strength leave such a smooth and uniform surface morphology. There are two different types of geometry seen here which argue against a simple overpressure of an intact case. First, overall, where the fracture meets the case circumference is perfectly uniform and straight all the way around the case. Second, on the microscopic scale, the surface of the failure is very smooth and has a perfectly uniform curve in two dimensions for its entire visible surface - there are no chevrons, dimples, or other hallmarks of a rupture in the metal. The evidence says it is a defect in manufacturing. Again, JMHO.

Yep. It's a clean separation.

 

[slikmrc]

My first thought looking at the pictures is why did the bolt face not contain the case head? I've seen a number of case head separations with swelled primer pockets and gas cutting on the bolt. But the bolt contained the case head, I'm wondering how there was room in chamber for the case head to straighten out like it did.

 

[Revolting Peasant]

Just glad you are ok. Could have easily lost some vision, lost an eye or finger, or way worse.
Now we just gotta start a GoFundMe to fix that mug…

 

[Seabeeken]

I use Manson AI headspace gauges because they are made to give you that .004" crush fit on the factory case and eliminate the need to seat bullets to jam. Otherwise, there is always a chance that seating a bullet to jam can be an issue f the bullet slips neck tension during firing pin strike and pushes case forward

 

[MagnumManiac]

I am so glad you feel so butt hurt that that is your response, small minds…

 

[243winxb]

gun explode

1. No crush fit when fire forming.

2. Neck tension - low to none.
3.Donuts
4.Bullet jam add 10,000 PSI.
5.Neck to chamber clearance- none.
6.Shoulder bump- to much.
7. Kaboom round 2100 fps, case fell out of chamber. 46 grs RL-17.
8. Separation at thickest part of web.
9. 308 to708, to much shoulder bump.
10. Brass defect.

we can only guess what was the main cause of the kaboom. Maybe more then 1?

 

[sturner]

Send the brass back to them
All I use is Lapua and I got thousands of pieces never seen that one before

 

[Willys]

Did you cut your other brass and look for thinning at the web. I have brass that will do this if I go past 7-8 reloads due to poor match between die and chamber.

 

[DoneNOut]

2. Neck tension - low to none.

It was mentioned not likely the culprit as benchrest shooters commonly use this level of neck tension. With all my might I cannot get the bullets to move pulling and pushing on them with my fingers.

3.Donuts

Those were eliminated before firing the 708AI

4.Bullet jam add 10,000 PSI.

I didn't jam the bullets

5.Neck to chamber clearance- none.

No, I had .007. I had none initially, but corrected with neck turning on the 708AI rounds

6.Shoulder bump- to much.

On the 708AI I only had .0015 bump. I couldn't bump any farther with my die set up. I even bought the Redding competition shell holders to get that .0015 because prior I wasn't able to bump any from fired shoulder length.

7. Kaboom round 2100 fps, case fell out of chamber. 46 grs RL-17.

It was determined that 46gr of RL17 isn't an overly pressured load.

8. Separation at thickest part of web.

Yup, but this was a result. Not an action

9. 308 to708, to much shoulder bump.

Yup

10. Brass defect.

Yup

we can only guess what was the main cause of the kaboom. Maybe more then 1?

Yup

 

[DoneNOut]

Did you cut your other brass and look for thinning at the web. I have brass that will do this if I go past 7-8 reloads due to poor match between die and chamber.

Not yet. I was using the paperclip method, but realized can't get low enough in the case to detect where this separation happened.

This brass was only shot 1 time prior. That fact adds to the mind blender. LOL

 

[Justice1327]

I honestly believe this is NOT an over pressure incident, if it were, the brass is normally fused around the bolt face. I am certain that is faulty brass from when extruded while being made. Lapua are one of the few that extrudes their brass instead of drawing it.

Cheers.

Can you explain the pro/cons of extruded vs draw brass? thank you

 

[DoneNOut]

So, there is also the "Ford Pinto" recall aspect to manufacturers, cost vs risk determination, and all that. Companies aren't gonna out the gate say their product failed. It opens them up to too much liability. Recalls and companies admitting known defects, unknown defects even, have a ton of legal challenge backing to motivate the companies to initiate a recall. The first step is to assign blame on the consumer and call operator error. So, with all that macro analysis on the issue, I'll go micro:

I appreciate the Lapua rep walking through every single little detail of my loading process with me. It was actually pretty fun. I learned a step in my process needed correction. Awesome!

Was it my fault? Possibly
Was it the brass fault(y)? Possibly

If it were the rule rather than exception for wildcat cartridges to kaboom from brass manipulation, nobody would even do it. Nobody says, "Oh your shooting AI cartridges? Yup, you'll blow your gun up!"