I had a partial case head separation using a 1.8oz buffer

[LRRPF52]

I understand safety at the field level, and the engineer is responsible for the system safety he develops or endorses.
I see trend specific to one component, and compelling explanation, combined with a large body of near-miss warning signs .

When you see a failure mode trend, and then see a difference that readily explains that failure mode - you call it out.

What I am also seeing, is what I see at the field level safety - of experts who have always said it is one thing, are the slowest to see the obvious when pointed out, and counter to their own bias.

Go look at those 4 photos, look at the fact that 3 kabooms in the last year - only with that brass, amd look at the warning tell of the ring shoulders. I'd fire an engineer who didn't call this out. It might also only fail in certain barrel at certain gas settings. Are you OK with that? I'm not.

From the engineering side, there are basic principles of pressure, axial stress, torsion, loads, factors of safety, metallurgy, etc.

These are all essential to know and be familiar with in firearms engineering, but you really need more specific experience in firearms engineering to understand what is going on.

I’ve seen several people in this industry now, including guys I highly respect who have done extremely well for themselves financially, who made some of the most egregious and erroneous statements about the basics of firearms engineering.

One of them, who went on to start and grow a very popular company, told me to my face that he thinks, “Bolt thrust is bullish*t.”

Bolt thrust is a fundamental reality of basic locking breach repeating firearms, where axial stress is placed on the bolt from the contained pressure in the system.

Same with bolt lug torsion on a rotating bolt design when the gas system is not timed correctly.

Metallic cartridge case metallurgy is also a fundamental discipline, where various manufacturers weigh the engineering and financial trade-offs as to how they will formulate their brass alloys.

Lapua chooses to focus on the best possible metallurgy, combined with tight tolerances on case dimensions internally and externally, with emphasis on measured aspects of flash hole performance relative to primer spark penetration depth into the propellant column.

The cheaper, softer brass manufacturers focus on volume production, so they make design trade-offs relative to areas of the case to keep them within FoS based on the SAAMI MAP, MPSM, and MPLM.

Cartridge manufacturers have to batch-test multiple samples within lots, which are then fired through instrumented and calibrated test breeches.

Reputable component manufacturers do their own testing, the more strenuous, the better their reputations tend to be.

Lapua has been the gold standard in that space for many decades.

A lot of people might read this and constrain my comments to their own situation, where they own and shoot only 1-2 of these firearms in this cartridge.

In reality, I have lost track of how many 6.5 Grendels I have tested over the years, while owning many, ranging from the longer barrels on down to the 12” guns.

I have had nothing but boringly-repeatable results with the Lapua brass. Then again, I’m very discerning about what barrels and chambers I use.

I have given some companies the benefit of the doubt by taking a chance with their barrels, bolts, and chambers.

Some worked out, and others didn’t.

I think this incident is starting to look more and more like a serious excess headspace problem, nothing to do with the brass.